CN111615503A

CN111615503A - Composite material, method for the production thereof and use thereof

Info

Publication number: CN111615503A
Application number: CN201780097871.1A
Authority: CN
Inventors: 拉里·E·麦坎德利什; 奥兰多·娜琳; 丹尼尔·卡斯特罗; 瓦西特·阿塔坎; 德温·帕滕; 约翰·P·库普勒; 肖恩·卡姆伦·奎恩
Original assignee: Solidia Technologies Inc
Current assignee: Solidia Technologies Inc
Priority date: 2017-12-04
Filing date: 2017-12-04
Publication date: 2020-09-01
Also published as: JP2023159143A; EA202091075A1; WO2019112555A1; EP3720828A4; JP2021505523A; CA3083371A1; BR112020011138A2; EP3720828A1

Abstract

The present invention provides a novel article of manufacture comprising a hollow interior channel or tube, or hollowed out composite material, and formulations and methods for making and using the same. These hollow articles are suitable for use in a variety of applications in construction, walkways, landscaping, and infrastructure.

Description

Composite material, method for the production thereof and use thereof

Technical Field

The present invention relates generally to composite articles and methods and process flows for making the same. More particularly, the present invention relates to novel composite articles or combinations of composite articles (e.g., paving materials, blocks, roof tiles, and hollow slabs) and formulations and methods for their manufacture and use. These concrete-type articles are suitable for use in a variety of applications such as construction, pavement, landscaping, and infrastructure.

Background

Concrete is the most consumed man-made material in the world. Typical concrete materials are made from a mixture of portland cement, water, and aggregate such as sand, crushed stone, and the like. Portland cement is a synthetic material made from a mixture of limestone flour and clay or similar materials by firing in a rotary kiln at a sintering temperature of about 1450 ℃.

Paving stones are concrete blocks produced by casting, punching, pressing or a combination of vibration and punching. Paving materials are typically laid in an interlocking manner. These paving materials are sometimes also referred to as paving stones. When these pavers are damaged during the lifetime, they can be replaced with a new one to avoid any interruption of use. The interlocking paving material may be designed to leave voids between the patterns for draining water to the underlying layer.

ASTM C936 provides the criteria that a cement paving material needs to meet, but is not limited to the following: an average compressive strength of 8,000 psi; the average water absorption is not more than 5%; it can endure at least 50 times of freeze-thaw cycle, and the average material loss is not more than 1%. In addition to ASTM requirements, it is also desirable that paving materials meet additional requirements, including, reduced efflorescence (e.g., reduced leaching of reaction products due to concentration gradients); good color retention; wear resistance according to the place of use of the paving material.

Like paving material, blocks are also precast concrete made by casting or stamping processes or similar pressing processes. The blocks may also be referred to as Concrete Masonry Units (CMUs), hollow blocks and concrete blocks. When these blocks are made from fly ash, they are referred to as cinder blocks. These blocks are typically hollow structures. Artificial or man-made paving materials have been studied in an effort to replace expensive and scarce natural materials with low-cost, easily produced imitations. However, such efforts have not yet been made in synthetic materials having the desired stone appearance, texture, density, hardness, porosity and other aesthetic characteristics, while being capable of being mass produced at low cost and with minimal environmental impact.

The blocks are expected to provide better structural performance than clay bricks (for load bearing masonry structures) and provide a smoother surface when producing masonry walls. Furthermore, the interlocking concrete masonry units do not require mortar to tie the units. The blocks can be used to construct hollow structures having superior sound and heat insulation effects compared to solid structures.

Typically, the blocks need to meet the requirements of ASTM C90, a standard specification for load bearing concrete masonry units. Blocks meeting this standard are assuredly acceptable in terms of strength, geometry, durability and fire resistance and are generally available for use in standard commercial construction projects.

Hollow slabs, sometimes referred to as hollow slabs or hollow slabs, are precast slabs of concrete. It is commonly used in building construction, for example in multi-storey buildings as a floor, wall or roof. Precast concrete slabs generally have tubular voids extending the entire length of the slab, making the slab lighter than a block floor of the same thickness or strength. The reduced weight reduces the cost of materials and transportation.

Conventional slabs are about 120cm wide with a standard thickness between 15cm and 50 cm. The precast concrete i-beams between the holes contain steel cables that provide bending resistance to bending moments from the load. The manufacturing process involves extruding wet concrete from a moving mold around the pre-stressed steel wire ropes. After curing, the continuous slab is cut to the desired length and width. Hollow floor slabs are also made of reinforced concrete (not prestressed). The hollow wall panel does not use steel bars.

However, concrete products are not optimal in terms of economic and environmental impact. The existing production technology has large energy consumption and large carbon dioxide emission, which causes unfavorable carbon footprint. The production of portland cement is not only an energy intensive process, but also a process that releases large amounts of greenhouse gases (CO 2). The cement industry accounts for about 5% of the worldwide anthropogenic carbon dioxide emissions. Wherein more than 60% of the CO2 comes from the chemical decomposition or calcination of limestone.

Recently, a revolutionary form of cement based on carbonatable calcium silicate materials has emerged, promising alternatives to traditional cements. The production of carbonatable calcium silicate based cements significantly reduces CO2 emissions and energy consumption. In addition, the novel cement can isolate CO when being cured into a concrete product₂Because CO2 needs to react with the carbonatable calcium silicate material during curing to form the concrete product.

Thus, there is a continuing need for new and improved cement and concrete products and production techniques that can be applied on a large scale at lower cost, yet improve energy consumption and a more desirable carbon footprint.

Disclosure of Invention

The present invention is based in part on the unexpected discovery of improved products and improved production techniques for producing various concrete articles (e.g., pavers, blocks, roof tiles, and hollow slabs) from carbonatable calcium silicate. The products produced have excellent physical and performance characteristics, including toughness, elasticity, wear resistance, and durability, comparable to or exceeding existing concrete products.

The concrete article of the invention can be readily produced from widely available, low cost raw materials by a low energy consumption production process suitable for large scale production, and therefore has a desirable carbon footprint and minimal environmental impact. The raw material comprises a precursor material, such as particulate calcium silicate. The calcium silicate precursor material typically comprises a mixture of discrete calcium silicate phases selected from one or more of CS (wollastonite or pseudo-wollastonite), C3S2 (wollastonite), C2S (belite, xonotlite (larnite) or metamwollastonite), and calcium silicate-based amorphous phases that comprise about 30% or more of the total phase, where "C" refers to calcium oxide or lime and "S" refers to silica or silica, as well as certain trace impurities and particulate filler materials that become bound units (e.g., calcium oxide-containing materials such as limestone, xonotlite, miso-silica (miro-silica) and quartz, lightweight aggregates such as perlite or vermiculite, and even industrial waste materials such as fly ash, bottom ash and slag). Fluid components are also provided as reaction media, including liquid water and/or water vapor and reagents, carbon dioxide (CO2), which is consumed as an active component during the production process and ultimately sequestered in the final product. The binding unit reacts under controlled temperature and pressure, or by means of hydration, wherein a reaction between water and water vapour takes place; or with steam and CO 2.

Various other additives may also be added, as desired by the end user, such as dispersing additives, rheology modifying additives (to improve the consistency of the mixture), color pigments, retarders and catalysts. The additive material may include natural or recyclable materials, as well as calcium carbonate-rich and magnesium carbonate-rich materials, and additives to the fluid components, such as water-soluble dispersants.

In one aspect, the present disclosure is generally directed to an article having a composite material dispersed as a plurality of discrete concrete articles. One or more pipes or channels between or through the plurality of discrete concrete items form a fluid transport system that is formed within the one or more pipes or channels and/or utilizes the exterior of the plurality of discrete items. The composite material comprises a plurality of bonding elements, wherein each bonding element has a center comprising primarily calcium silicate, a first or inner layer rich in carbon dioxide, and a second or outer layer rich in calcium carbonate; and filler particles comprising coarse filler particles and/or fine filler particles. The plurality of binding units and the plurality of filler particles together form one or more binding matrices in which the binding units and filler particles are uniformly dispersed and bound to each other. In certain embodiments, the plurality of discrete concrete objects are disposed within a housing or chamber.

In another aspect, the present disclosure is generally directed to a system for manufacturing an article. The system includes a housing or chamber and a composite material dispersed as a plurality of discrete concrete items enclosed therein. One or more pipes or channels disposed between or through the plurality of discrete concrete articles for forming a fluid transport system formed within and/or utilizing the exterior of the plurality of discrete articles. Optionally, the system further comprises one or more panels on which the plurality of discrete concrete items are placed, and one or more shelves, tarpaulins, walls or panels of curved, flat, convex or concave surfaces that form one or more conduits or channels in the fluid delivery system and facilitate fluid flow conditions.

In another aspect, the present disclosure is generally directed to a process for producing a manufactured article. The process comprises the following steps: mixing the particulate component with the liquid component to form a mixture; performing a casting or extrusion or other processing method that forms a mixture in a mold to produce a cast or extruded or otherwise formed green body comprising a plurality of discrete concrete articles, wherein one or more conduits or channels are disposed between or through the exterior of the plurality of discrete concrete articles; maintaining a CO2 atmosphere and/or a water vapor atmosphere in the one or more internal ducts or channels and outside the plurality of discrete articles; and curing the plurality of discrete articles under an atmosphere of water and/or CO2 at a pressure ranging from ambient atmospheric pressure to about 60psi above ambient atmospheric pressure, at a concentration of carbon dioxide ranging from about 10% to about 90%, and at a temperature ranging from about 20 ℃ to about 150 ℃ for about 1 hour to about 80 hours.

In certain particular embodiments, maintaining a CO2 and/or water vapor atmosphere in one or more internal ducts or channels and/or in the exterior of a plurality of discrete articles includes: filling an atmosphere in the exterior of the one or more internal channels and/or the plurality of discrete articles; recycling the filled CO2 and/or water vapor atmosphere; removing or adding water vapor to the filled atmosphere; and heating the filled atmosphere.

In another aspect, the present invention is generally directed to an article of manufacture made using the process flow described herein. The article of the invention may be of any suitable size or shape or for any suitable purpose, for example selected from paving, masonry, roof tile, hollow slab, precast concrete article with or without rebar.

Drawings

The objects and features of the present invention can be better understood with reference to the drawings described below, and the claims. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the drawings, like numerals refer to like parts throughout the different views.

FIG. 1 is a diagram showing the presence of a reversible reaction

Pressure-temperature phase diagram of the phases in (1).

FIG. 2 is a diagram showing the presence of a reversible reaction

Pressure-temperature phase diagram of the phases in (1).

FIG. 3 is a phase diagram of a CaO-SiO2-CO2 system at a pressure of 1 kbar.

FIG. 4 shows a reversible reaction

Pressure-temperature phase diagram of the phases present in (a).

FIG. 5 is a graph showing the reversible reaction as a function of the proportion of inert gas CO2

Pressure-temperature phase diagram of equilibrium curve.

FIG. 6 shows CaCO₃-MgCO₃Temperature-composition phase diagram of stability region of each phase in the system.

FIG. 7 is a tetrahedral diagram showing the phase relationship between the compounds CaO, MgO, O2 and CO2, and showing the CO2 starvation region (shaded) under the Cc-Di-Wo and Cc-Wo-Mo planes, where Cc represents calcite, Wo represents wollastonite, Ak represents akermanite, Di represents diopside, and Mo represents forsterite (CaMgSiO 4).

FIG. 8 is a monotropic graph showing the compounds CaO, MgO, SiO using a quaternary invariant point emanating from quaternary invariant points involving calcite (Cc), diopside (Di), forsterite (Fo), calcibolite (Mo), akermanite (Ak), and carbon dioxide phases₂And CO2, with the inset being a ternary system phase diagram including CaCO3, MgO, and SiO 2.

FIG. 9 is a schematic diagram of a CO2 composite curing chamber providing humidification in accordance with the principles of the present invention.

Fig. 10 is a schematic diagram of a curing chamber having multiple humidity control methods and capable of controlling and supplementing CO2 with constant flow or pressure regulation and temperature control in accordance with the principles of the present invention.

FIGS. 11(a) -11(c) are schematic diagrams of cross-sections of binding units according to exemplary embodiments of the invention, wherein the binding units comprise three exemplary core morphologies: (a) a fibrous shape, (b) an elliptical shape, and (c) an equiaxed shape.

12(a) -12(f) are schematic diagrams of side and cross-sectional views of composite materials according to exemplary embodiments of the invention showing (a) 1-dimensional oriented fibrous binding units in a sparsely bound matrix (the binding units are not in contact); (b) 2-dimensionally oriented platelet-shaped binding elements in a sparsely bound matrix (the binding elements are not in contact); (c) 3-dimensionally oriented platelet-shaped binding units in a loosely bound matrix (the binding units are not in contact), and (d) randomly oriented platelet-shaped binding units in a loosely bound matrix (the binding units are not in contact), wherein the composite comprises a binding matrix and a filler component such as a polymer, metal, inorganic particles, aggregate, or the like; (e) a densely bound matrix of binding units (having a volume fraction sufficient to establish a percolating network), wherein the matrix is in a 3D orientation; and (f) a densely bound matrix of randomly oriented binding units (having a volume fraction sufficient to establish a percolating network) which may contain filler components such as polymers, metals, inorganic particles, aggregates, and the like.

Fig. 13 shows a schematic diagram of an example of a binding unit using energy dispersive X-ray spectroscopy (EDS) chemical profiles of the binding matrix according to an exemplary embodiment of the present invention shown in (a) - (c) thereof, wherein the overlap of the si (a) and ca (b) profiles is shown. In which (c) CaSiO, SiO are indicated by arrows₂And CaCO₃And (4) a region. Fibrous wollastonite (CaSiO3) core particles are surrounded by SiO2 rich regions and by CaCO3 particles.

Fig. 14 shows an exemplary embodiment in which a plurality of discrete articles (201) are dry cast onto a plate (202) and placed within a housing or chamber (203). Fluid directionally flows between one or more pipes or channels (101), between the exterior of the plurality of discrete articles and the housing or chamber (102), and between the plurality of discrete concrete articles and the chamber assembly (103). In this example, the chamber component is a plate. Other embodiments of chamber components, such as baffles, flow conditioning and directing plates, rack components and the like.

Fig. 15 is a schematic view of a curing system with an adjustable support. The height of the passage between the top of the concrete item to the bottom of the next product plate (101) is adjustable to vary the flow rate of the process gas (102).

Fig. 16 is a schematic diagram of an example of a curing system with reversible airflow. The curing system may change the direction of the air flow following the direction shown by arrows (101) and (102). The flow and direction of the gas is controlled by an external conditioning system connected to the system on the flange, marked (103).

FIG. 17 is an enlarged view of an example of a curing system with reversible airflow. The curing system is designed with an air intake space to distribute air flow to the concrete article (101) and the channels formed by the outer surface of the concrete article and the chamber walls (102).

Figure 18 shows an example of a hollow slab manufactured according to the invention.

Fig. 19 shows an exemplary embodiment of the invention in which the flow of CO2 and water vapor may be controlled such that the flow oscillates in all directions as it passes through the inner duct or channel and around the outer surface to establish a time-averaged mirror symmetry along the length while maintaining side-to-side mirror symmetry. The symmetry reduces the effects of temperature and gas composition gradients that occur during curing.

Fig. 20 shows an example of measuring chamber humidity at the end wall using a visala (Vaisala) sensor throughout the curing process, and the cumulative amount of condensate collected throughout the run.

Fig. 21 is a schematic view of a solidification apparatus for solidifying the dry hollow castings.

FIG. 22 is an illustration of a hollow casting solidified in the apparatus of FIG. 21.

Detailed Description

The present invention provides an excellent concrete article having physical and performance characteristics comparable to or superior to those of existing concrete articles. The concrete article of the present invention can be readily produced from widely available, low cost raw materials by a production process suitable for large-scale production with improved energy consumption, reduced production cycle time (e.g., reduced curing time), and a more desirable carbon footprint. The generation process of the present invention consumes a large amount of CO2 to produce a CO2 sequestered product, thereby making it carbon neutral and environmentally friendly. Concrete articles herein refer to articles and articles having geometries typical of the consumer market, including but not limited to: paving material, bricks, segmental retaining walls, wet cast stone slabs, Concrete Masonry Units (CMU) or concrete hollow objects. Hollow articles herein refer to articles and articles having a hollow, channel, or other hollowed-out form (e.g., to reduce diffusion distances and promote curing).

The concrete article of the invention can be used as various building and construction components including, for example, sidewalks, floors, roofs, walls, doors, slabs, bridges, frames, passageways, partitions, linings, foundations, fences, acoustic panels, pipes, culverts (culverts vaults), septic tanks, drainage wells, and storm drains. They may be manufactured with or without embedded reinforcing elements (e.g., pre-tensioned and/or post-tensioned and/or pre-stressed) and are characterized by improved load bearing and durability of the article. The reinforcing component herein may be a solid bar, wire or cable (cable) made of a material having the desired characteristics, such as steel, polymeric material, glass, or a combination thereof.

In one aspect, the present invention generally relates to an article made of a composite material dispersed into a plurality of discrete concrete articles. One or more pipes or channels are provided between or through the plurality of discrete concrete items to form a fluid transport system that is located within and/or utilizes the exterior of the plurality of discrete objects. The composite material comprises: a plurality of bonding elements, each bonding element comprising a core comprising primarily calcium silicate, a first or inner silica-rich layer and a second or outer calcium carbonate-rich layer; and filler particles comprising coarse filler particles and/or fine filler particles. The plurality of binding units and the plurality of filler particles together form one or more binding matrices, wherein the binding units and the filler particles are substantially uniformly dispersed in the binding matrices and bound to each other.

One of the main features of the article of the invention is that the internal volume created by the ducts or channels (including the hollow spaces) is of a smaller thickness compared to the overall volume of the article. Contacting the curing liquid to the side of the internal volume significantly increases the surface area to which carbon dioxide and water must diffuse, thereby affecting curing. Furthermore, the conduits or channels reduce overall material usage and product weight for the whole, thereby saving material and other associated costs in transportation and installation.

In certain embodiments, the plurality of discrete concrete items are disposed within a chamber or housing, and for the purposes of the present invention, the terms "chamber" and "housing" are used interchangeably.

When mass produced, the concrete articles may be arranged or oriented during the molding process or during the loading of the curing chamber to align the inner or outer surfaces for maximum exposure to the curing liquid (e.g., CO2 and water vapor) and to minimize the diffusion distance of CO2 and water relative to the total volume of the discrete articles. Arranging the inner or outer surface of the discrete article with respect to fluid flow conditions is a key consideration in ensuring a uniform and/or rapid curing process.

The discrete articles may be arranged in the curing chamber for fluid flow conditions to maximize diffusion of carbon dioxide and water. The spacing between the concrete articles arranged within the chamber can be controlled to create channels parallel to the fluid flow while maintaining similar concrete shell volumes. The fluid flow concentration of the surface of the discrete article exposed in the channel increases the uniformity and/or speed of curing. The geometry of the discrete articles and the fluid flow conditions of the curing system determine the optimum inter-article spacing, article orientation, and spacing between the discrete articles and the fluid distribution system to induce carbon dioxide and water to pass through the surface of the article in which the channels are formed at a high diffusion rate.

Controlling the spacing between the concrete article arranged within the chamber and the chamber components (e.g. shelves, plates) and the fluid distribution components (e.g. gas inlets, outlets, plenums or perforated plates) creates a channel between the surface of the concrete article and the surface of the chamber components.

The surface of the discrete article in the vicinity of a chamber component, such as a shelf, creates a channel adjacent to and/or between the discrete article and the chamber, in which channel the fluid flow is concentrated. The concentration of fluid flow in the channels between the discrete object surface and the chamber assembly improves curing uniformity and speed. The geometry of the discrete article and the fluid flow conditions of the curing system determine the optimum article orientation, the spacing between the discrete article and the chamber assembly and the spacing between the discrete article and the fluid distribution system, inducing carbon dioxide and water to pass through the surface of the article in which the channels are formed at a high diffusion rate.

In certain embodiments, each of the plurality of discrete concrete articles does not include any reinforcing component.

In certain embodiments, each of the plurality of discrete concrete articles includes one or more reinforcing elements embedded therein.

In certain embodiments, the one or more reinforcing ingredients are selected from the group consisting of rods, wires, and cables. The one or more reinforcing components may be made of any suitable material, such as iron, steel, polymeric materials, glass, or combinations thereof.

In certain embodiments, the plurality of binding units are derived from a ground calcium silicate composition via chemical transformation, such ground calcium silicate composition comprising one or more of natural or synthetic wollastonite, pseudo-wollastonite, gefite, gehlenite, monetite, and an amorphous phase.

In certain embodiments, the gas comprises carbon dioxide. In certain embodiments, the plurality of binding units are prepared by chemical conversion by reacting ground calcium silicate with CO2 by a controlled hydrothermal liquid phase sintering process.

In certain embodiments, the gas comprises carbon dioxide. In certain embodiments, the plurality of binding units are made from chemical conversion of a precursor calcium silicate other than synthetic wollastonite or pseudo-wollastonite.

In certain embodiments, the weight ratio of binding units to filler particles is about 1: 5.

In certain embodiments, the plurality of discrete concrete articles has a water absorption of less than about 10%.

In certain embodiments, the fluid transport system is adapted to flow a gas through one or more conduits or channels and the exterior of the plurality of discrete articles.

In certain embodiments, fluid flowing through the exterior of the one or more conduits or channels and the plurality of discrete articles changes direction at least once.

In certain embodiments, the fluid flowing through the exterior of the one or more conduits or channels and the plurality of discrete articles changes velocity at least once.

In certain embodiments, the fluid transport system within the exterior of the plurality of discrete articles includes flow between housings or chambers or chamber components within the housings or chambers.

Any suitable calcium silicate composition may be used as a precursor for the binding unit. The term "calcium silicate composition" as used herein generally refers to a natural mineral or synthetic material comprising one or more groups of calcium silicates, the calcium silicate phase comprising CS (wollastonite or pseudo-wollastonite, and sometimes the formula CaSiO. RTM. is used₃Or CaO. SiO₂Expressed), C3S2 (wollastonite, and sometimes the formula Ca is used₃Si₂O₇Or 3 CaO.2SiO₂Represented by general formula (I), C2S (dicalcium silicate, β -Ca)₂SiO₄Or xonotlite (larnite), β -Ca₂SiO₄Or bredigite (bredigite), α -Ca₂SiO₄Or gamma-Ca₂SiO₄And sometimes formula Ca is used₂SiO₄Or 2 CaO. SiO₂Expressed), calcium silicate based amorphous phases, wherein each material may include one or more other metal ions and oxides (e.g., aluminum, magnesium, iron, or manganese oxides), or mixtures thereof, or may include an amount of magnesium silicate, either in natural or synthetic form, in amounts ranging from trace amounts (1%) to about 50% or more by weight.

In addition to the above crystalline phases, the calcium silicate composition may also comprise an amorphous (non-crystalline) calcium silicate phase. The amorphous phase may additionally comprise Al, Fe and Mg ions as well as other impurity ions present in the raw material. The calcium carbonate composition may also contain small amounts of residual CaO (lime) and SiO2 (silica). The calcium silicate composition may also contain a small amount of C3S (tricalcite, Ca2SiO 5).

The calcium silicate composition may also contain a large amount of an inert phase, such as those of the formula (Ca, Na, K)₂[(Mg,Fe²⁺,Fe³⁺,Al,Si)₃O₇]The melilite type mineral (melilite or gehlenite or akermanite) and the general formula of Ca₂(Al,Fe³⁺)₂O₅Ferrite type minerals (ferrite or mayenite or C4 AF). In certain embodiments, the calcium silicate comprises only crystalline phases; in certain embodiments, some of the calcium silicate compositions are present as amorphous phases and some are present as crystalline phases.

It is noted that preferably the calcium silicate composition of the invention is not hydrated. However, minor amounts of hydratable calcium silicate phases (e.g., C2S, C3S, and CaO) may be present. C2S exhibited slow hydration kinetics when exposed to water and rapidly converted to CaCO3 during CO2 curing. C3S and CaO hydrate rapidly upon exposure to water and should therefore be limited to < 5% by mass.

In certain preferred embodiments, the molar ratio of elemental Ca to elemental Si in the calcium silicate composition is from about 0.80 to about 1.20. In certain preferred embodiments, the molar ratio of elemental Ca to elemental Si in the calcium silicate composition is from about 0.85 to about 1.15. In certain preferred embodiments, the molar ratio of elemental Ca to elemental Si in the calcium silicate composition is from about 0.90 to about 1.10. In certain preferred embodiments, the molar ratio of elemental Ca to elemental Si in the calcium silicate composition is from about 0.95 to about 1.05. In certain preferred embodiments, the molar ratio of elemental Ca to elemental Si in the calcium silicate composition is from about 0.98 to about 1.02. In certain preferred embodiments, the molar ratio of elemental Ca to elemental Si in the calcium silicate composition is from about 0.99 to about 1.01.

The metal oxides of Al, Fe and Mg contained in the calcium silicate composition are generally controlled to be less than about 30%. In certain preferred embodiments, the composition includes about 20% or less of metal oxides of Al, Fe, and Mg by mass of the total oxides. In certain preferred embodiments, the composition includes about 15% or less of metal oxides of Al, Fe, and Mg by mass of the total oxides. In certain preferred embodiments, the composition includes about 12% or less of metal oxides of Al, Fe, and Mg by mass of the total oxides. In certain preferred embodiments, the composition includes 10% or less of metal oxides of Al, Fe, and Mg by mass of the total oxides. In certain preferred embodiments, the composition includes 5% or less of metal oxides of Al, Fe, and Mg by mass of the total oxides.

Each of the calcium silicate phases is suitable for carbonation with CO 2. Discrete calcium silicate suitable for carbonation reactions is hereinafter referred to as the reaction phase.

The various reaction phases may comprise any suitable portion of the total reaction phase. In certain preferred embodiments, the CS reaction phase comprises about 10 to about 60 wt.% (e.g., about 15 wt.% to about 60 wt.%, about 20 wt.% to about 60 wt.%, about 25 wt.% to about 60 wt.%, about 30 wt.% to about 60 wt.%, about 35 wt.% to about 60 wt.%, about 40 wt.% to about 60 wt.%, about 10 wt.% to about 50 wt.%, about 10 wt.% to about 40 wt.%, about 10 wt.% to about 30 wt.%, about 10 wt.% to about 25 wt.%, about 10 wt.% to about 20 wt%); C3S2 comprises about 5 to about 50 wt% (e.g., about 10 wt% to 50 wt%, about 15 wt% to 50 wt%, about 20 wt% to 50 wt%, about 30 wt% to 50 wt%, about 40 wt% to 50 wt%, about 5 wt% to 40 wt%, about 5 wt% to 30 wt%, about 5 wt% to 25 wt%, about 5 wt% to 20 wt%, about 5 wt% to 15 wt%); and C2S comprises about 5 wt% to 60 wt% (e.g., about 10 wt% to about 60 wt%, about 20 wt% to about 60 wt%, about 25 wt% to about 60 wt%, about 30 wt% to about 60 wt%, about 35 wt% to about 60 wt%, about 40 wt% to about 60 wt%, about 5 wt% to about 50 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 30 wt%, about 5 wt% to about 25 wt%, about 5 wt% to about 20 wt%); and C comprises about 0 wt% to 3 wt% (e.g., 0 wt%, 1 wt% or less, 2 wt% or less, 3 wt% or less, about 1 wt% to 2 wt%, about 1 wt% to 3 wt%, about 2 wt% to 3 wt%).

In certain embodiments, the reaction phase comprises a calcium silicate-based amorphous phase, e.g., about 40% or more (e.g., about 45% or more, about 50% or more, about 55% or more, about 60% or more, about 65% or more, about 70% or more, about 75% or more, about 80% or more, about 85% or more, about 90% or more, about 95% or more) amorphous phase by mass of the total phase. It is noted that the amorphous phase may additionally include impurity ions present in the starting material.

The calcium silicate compositions of the invention are suitable for carbonation reactions with CO 2. In particular, calcium silicate compositions are suitable for carbonation with CO2 to form CaCO3 with a 20% or more mass increase at temperatures of about 30 ℃ to about 90 ℃. The increased mass reflects a net sequestration of CO2 in the carbonated product. In certain preferred embodiments, the composition is suitable for carbonation with CO2 at a temperature of from about 30 ℃ to about 90 ℃ (e.g., from 40 ℃ to about 90 ℃, from about 50 ℃ to about 90 ℃, from about 60 ℃ to about 90 ℃, from about 30 ℃ to about 80 ℃, from about 30 ℃ to about 70 ℃, from about 30 ℃ to about 60 ℃, from about 40 ℃ to about 80 ℃, from about 40 ℃ to about 70 ℃, from about 40 ℃ to about 60 ℃) to form CaCO3 with a 10% or more (e.g., 15% or more, 20% or more, 25% or more, 30% or more) mass increase.

Precursor calcium silicate compositions are typically used in powder form having an average particle size (d50) of from about 8 μm to about 25 μm, with 10% of the particle sizes (d10) being less than about 0.1 μm to about 3 μm and 90% of the particle sizes (d90) being greater than about 35 μm to about 100 μm.

In certain embodiments, by selecting d90: the ratio of d10 may improve powder flow or reduce the amount of water required in casting. In certain embodiments, by selecting d 50: the ratio of d10 may improve reactivity, improve agglomeration, or reduce the amount of water required for casting. In certain embodiments, the ratio of d90: d50 may be selected to provide reactivity, improve agglomeration, or reduce the amount of water required for casting.

Any suitable filler particles may be used, for example, calcium oxide-containing or silica-containing materials. Exemplary filler particles include lime, quartz (containing sand), wollastonite, xonotlite, calcined oil shale, fly ash or pozzolan, kiln dust, ground clay, pumice dust. Materials such as industrial waste (e.g. fly ash, slag, silica fume) can also be used as fillers. In certain preferred embodiments, lightweight aggregates such as perlite or vermiculite may also be used as fillers. In certain preferred embodiments, the filler particles are made of a calcium oxide-rich material such as ground lime.

The filler particles comprise calcium oxide or silica, and the particle size (d50) of the filler particles is in a range from about 0.25 μm to about 200 μm (e.g., from about 0.25 μm to about 150 μm, from about 0.25 μm to about 100 μm, from about 0.25 μm to about 50 μm, from about 0.25 μm to about 20 μm, from about 0.25 μm to about 10 μm, from about 0.5 μm to about 200 μm, from about 1 μm to about 200 μm, from about 5 μm to about 200 μm, from about 10 μm to about 200 μm, from about 20 μm to about 200 μm, from about 50 μm to about 200 μm).

In certain embodiments, the filler particles are selected from fly ash, bottom ash, slag having a particle size ranging from about 0.5 μm to about 300 μm (e.g., from about 1 μm to about 300 μm, from about 5 μm to about 300 μm, from about 10 μm to about 300 μm, from about 50 μm to about 300 μm, from about 100 μm to about 300 μm, from about 0.5 μm to about 200 μm, from about 0.5 μm to about 100 μm, from about 0.5 μm to about 50 μm, from about 0.5 μm to about 20 μm, from about 0.5 μm to about 10 μm, from about 0.5 μm to about 5 μm).

In an exemplary embodiment of the carbonation of the calcium silicate composition of the present invention, the ground calcium silicate particles used have a particle size with a cumulative 10% of the diameter greater than 1 μm in the volume distribution of the particle size distribution.

In certain embodiments, the filler particles are selected from limestone, Millipore and quartz having particle sizes ranging from about 1 μm to about 500 μm (e.g., from about 1 μm to about 400 μm, from about 1 μm to about 300 μm, from about 1 μm to about 200 μm, from about 1 μm to about 100 μm, from about 1 μm to about 50 μm, from about 1 μm to about 30 μm, from about 5 μm to about 500 μm, from about 10 μm to about 500 μm, from about 20 μm to about 500 μm, from about 50 μm to about 500 μm, from about 100 μm to about 500 μm, from about 200 μm to about 500 μm).

In certain embodiments, the filler particles are selected from lightweight aggregates having particle sizes ranging from about 20 μm to about 500 μm (e.g., from about 20 μm to about 400 μm, from about 2 μm to about 300 μm, from about 20 μm to about 200 μm, from about 20 μm to about 100 μm, from about 50 μm to about 500 μm, from about 100 μm to about 500 μm, from about 200 μm to about 500 μm, from about 300 μm to about 500 μm).

In certain embodiments, the set control agent is selected from gluconate and sucrose. In certain embodiments, the dispersion/viscosity modifier is a polycarboxylate-based material.

In an exemplary embodiment, the ground calcium silicate is ground wollastonite, the filler particles comprise ground limestone and silica, the activator is ground lime, the set control agent is a gluconate, the viscosity modifier is a polycarboxylate-based material, and the aerating agent is aluminum paste.

It should be understood that the calcium silicate compositions, phases, and methods disclosed herein may take the form of using a magnesium silicate phase instead of or in addition to a calcium silicate phase. The term "magnesium silicate" as used herein refers to a natural mineral or synthetic material including one or more of the group of magnesium and silicon containing compounds including, for example, Mg2SiO4 (also known as "forsterite") and Mg3Si4O10(OH)2 (also known as "talc"), wherein the material may contain one or more other metal ions and oxides (e.g., oxides of calcium, aluminum, iron or manganese) or mixtures thereof, or may also contain a large amount of calcium silicate in either natural or synthetic form ranging from trace amounts (1 wt%) to about 50% or more by weight.

The term "quartz" as used herein refers to any SiO 2-based material, including ordinary sand (buildings and masonry), as well as glass and recycled glass. The term also includes any other recoverable natural and synthetic material containing significant amounts of SiO2 (e.g., mica, sometimes also represented by the formula KAl2(AlSi3O10) (OH) 2).

In another aspect, the present disclosure is generally directed to a system for manufacturing an article. The system includes a housing or chamber and enclosed therein a composite material dispersed as a plurality of discrete concrete items. One or more pipes or channels are provided between or through the plurality of discrete concrete items to form a fluid transport system that is located within the one or more pipes or channels and that utilizes the exterior of the plurality of discrete objects. The system also optionally includes one or more panels on which the plurality of discrete concrete items are placed, and one or more shelves, tarps, walls or panels having curved, planar, convex or concave surfaces that form one or more conduits or channels in the fluid delivery system and promote fluid flow conditions.

In certain embodiments, the system includes a fluid dispensing assembly that controls at least a portion of the fluid flow conditions in the housing or chamber.

In certain embodiments, the system includes a fluid dispensing assembly that controls fluid flow conditions throughout the housing or chamber.

In certain embodiments, a fluid distribution assembly that controls fluid flow conditions throughout the housing or chamber changes the direction of the airflow at least once.

In certain embodiments, a fluid distribution assembly that controls fluid flow conditions throughout the housing or chamber varies at least one primary gas flow rate.

In certain embodiments, the fluid distribution assembly comprises one or more fluid inlets, outlets, plenums, or perforated plates, or combinations thereof.

In certain embodiments, the housing or chamber is made of a material selected from a metal, an alloy, a plastic, a polymer matrix composite, a ceramic composite, or a combination thereof. In certain embodiments, the housing or chamber is made of a concrete material, or steel, or tarpaulin, or a combination thereof.

In another aspect, the present disclosure is generally directed to a process for producing a manufactured article. The process comprises the following steps: mixing a particulate component with a liquid component to form a mixture; performing a casting or extrusion or other processing method that forms a mixture in a mold to produce a cast or extruded or otherwise formed green body comprising a plurality of discrete concrete articles, wherein one or more conduits or channels are disposed between or through the exterior of the plurality of discrete concrete articles; maintaining a CO2 atmosphere and/or a water vapor atmosphere in the one or more internal ducts or channels and outside the plurality of discrete articles; and curing the plurality of discrete articles under an atmosphere of water and/or CO2 at a pressure ranging from ambient atmospheric pressure to about 60psi above ambient atmospheric pressure, at a concentration of carbon dioxide ranging from about 10% to about 90%, and at a temperature ranging from about 20 ℃ to about 150 ℃ for about 1 hour to about 80 hours.

In certain embodiments, maintaining a CO2 and/or water vapor atmosphere in one or more internal ducts or channels and/or in the exterior of a plurality of discrete articles comprises: filling an atmosphere in the exterior of the one or more internal channels and/or the plurality of discrete articles; recycling the filled CO2 and/or water vapor atmosphere; removing or adding water vapor to the filled atmosphere; and heating the filled gas.

In certain embodiments, maintaining a CO2 and/or water vapor atmosphere in one or more internal conduits or channels comprises changing the direction and speed of CO2 and/or water vapor fluid flow at least once during curing of the body.

In certain embodiments, the particulate composition comprises ground calcium silicate, including one or more of natural or synthetic wollastonite, pseudo-wollastonite, gefite, gehlenite, dicalcium silicate and tricalcite, having an average particle size in the range of from about 1 μm to about 100 μm, and the liquid component comprises water.

In certain embodiments, the cast mixture is cured at a temperature of 60 ℃ or less, in a vapor atmosphere comprising water and CO2, at atmospheric pressure, for about 10 to about 50 hours.

In certain embodiments, the ground calcium silicate is substantially ground wollastonite.

In certain embodiments, the process further comprises embedding one or more reinforcing ingredients in the mixture.

The one or more reinforcing components may be made of any suitable material, such as iron, steel, polymeric materials, glass, or combinations thereof.

The one or more reinforcing components may be of any suitable size or shape, e.g., in the form of rods, wires, and cables.

In another aspect, the present disclosure is generally directed to an article made by the process disclosed herein.

The article may be of any suitable size or shape or for any suitable purpose, for example selected from paving, bricks, roof tiles, hollow slabs, precast concrete articles with or without reinforcing elements.

The one or more conduits or channels (containing hollow spaces) are an important feature and affect the overall properties and performance of the discrete article, including overall weight, mechanical properties and function. The discrete articles, with the chamber assembly and the chamber itself, may form any suitable number of conduits or channels in a predesigned pattern and interconnecting relationship. The conduits or channels may take any suitable size and shape (e.g., circular, oval, polygonal, rectangular, or square). They may be arranged in any suitable pattern and interconnection.

The number, shape, size and configuration of the conduits or channels will affect various mechanical properties of the hollow article. As discussed in more detail herein, the number, shape, size, and configuration of the conduits or channels may be utilized to optimize the manufacturing process, e.g., to speed up the curing process and achieve a more uniform cure.

The volume of the conduit or channel can account for any suitable volume fraction of the plurality of discrete articles, for example, from about 5 vol.% to about 95 vol.% (e.g., from about 10 vol.% to about 95 vol.%, from about 20 vol.% to about 95 vol.%, from about 30 vol.% to about 95 vol.%, from about 50 vol.% to about 95 vol.%, from about 70 vol.% to about 95 vol.%, from about 5 vol.% to about 90 vol.%, from about 5 vol.% to about 70 vol.%, from about 5 vol.% to about 50 vol.%, from about 5 vol.% to about 30 vol.%, from about 5 vol.% to about 20 vol.%), depending on the geometry of the product mold and any post-molding product spacing variations.

The discrete articles of the present invention can be made in any size and dimension. Typical dry cast paving materials range in height from 40mm to 120mm and may be pressed to1.45m × 1.45m size to distribute the plurality of concrete items up to 0.26m per product panel³For example, a typical dry cast Concrete Masonry Unit (CMUs) is 200mm high and may be pressed to a size of 1.45m × 1.45.45 m to distribute the plurality of concrete objects up to 0.43m per product panel³The volume of (a). The number, shape, size and configuration of the channels can be used to improve curing speed and uniformity, thereby enhancing the manufacturing process.

In certain embodiments, wherein the discrete articles are paving material, the dimensions range from 1 inch to 24 inches long, 1 inch to 24 inches wide, and 0.5 inch to 6 inches high. In certain embodiments, the dimensions are 4 inches to 12 inches long, 4 inches to 12 inches wide, and 1.5 inches to 5 inches high.

In certain embodiments, the discrete articles are blocks having dimensions ranging from 71/2 inches to 16 inches long, 31/2 inches to 12 inches wide, and 4 inches to 16 inches high. In certain embodiments, the dimensions are 71/2 inches to 16 inches long by 31/2 inches to 12 inches wide by 6 inches to 12 inches high.

In certain embodiments, wherein the discrete articles are roofing tiles, the dimensions range from 2 inches to 24 inches long, 2 inches to 24 inches wide, and 0.25 inches to 2 inches thick. In certain embodiments, the dimensions are 4 inches to 12 inches long, 4 inches to 12 inches wide, and 0.25 inches to 1 inch thick.

In certain embodiments, wherein the discrete articles are slabs, the dimensions range from 4 inches to 48 inches long, 4 inches to 48 inches wide, and 1.5 inches to 5 inches high. In certain embodiments, it is sized to be 4 inches to 48 inches long, 4 inches to 48 inches wide, 1.5 inches to 5 inches high, and typically occupies a footprint in excess of 144 square inches.

Concrete articles are typically pressed on the production slab in a manner that maximizes the volume of concrete produced on each slab. When a uniform transverse geometry of the product is produced, parallel voids are left between the articles, thereby forming channels between the plurality of discrete articles. The number, shape, size and configuration of the channels may also be used to optimize manufacturing, for example, to speed up the curing process and achieve more uniform curing.

Loading the plurality of concrete articles into the chamber in a regular manner. In certain embodiments, the curing chamber forms a chamber or enclosure. Within the chamber, the plates are stacked or placed for curing. In the chamber, the orientation and spacing of the plates can be controlled to create channels consisting of the outer planar faces of a plurality of discrete articles, consisting of a plurality of individual article faces, and a chamber assembly (e.g., another stacked production plate), which can direct fluid flow. The geometry of the discrete articles and the fluid flow conditions of the curing chamber determine the optimum article orientation, spacing between the article and the chamber assembly and spacing between the article and the fluid distribution system to induce carbon dioxide and water to pass through the surface of the article in which the channels are formed at a high diffusion rate.

In certain embodiments, the concrete mold used to produce a set of discrete objects is modified to vary the spacing between the plurality of discrete objects according to the fluid distribution within the chamber and to increase the rate at which carbon dioxide and water diffuse across the surface of the objects forming the channels.

In certain embodiments, after the forming operation, the discrete articles are separated or otherwise moved according to chamber fluid flow conditions to vary the spacing between concrete articles and increase the rate of diffusion of carbon dioxide and water across the surface of the article forming the channel.

In certain embodiments, the spacing of the product plates and/or the orientation of the product plates can be adjusted relative to the fluid dispensing system to increase the fluid flow through the channels formed by the plurality of discrete articles and the outer surface of the housing, and the outer surface of the plurality of discrete articles and the chamber assembly. This increases the rate of diffusion of carbon dioxide and water between the plurality of discrete articles and the associated exterior surface of the chamber and the associated exterior surface of the plurality of discrete articles and the chamber assembly.

In certain embodiments, the step of forming the mixture comprises/involves mixing aggregate, sand, calcium silicate and water in a mixer. The mixer may be of any type commonly used for mixing conventional concrete. The well-mixed solids are slightly wetted with aggregate, sand and sufficient water. The calcium silicate is then added to the batch together with the remaining water and any additives. The mixture was mixed thoroughly and the water was adjusted to achieve the desired humidity level.

In certain preferred embodiments, the step of casting or extruding the olefinic pulp compound in a mould comprises/involves pouring the compound into a mould or extruder configured to produce a cast or extruded or otherwise formed body having one or more internal conduits or channels. For example, in the case of making castings, vibration may be applied by vibrating the mold or inserting a vibrating rod into the mix in the mold to assist in removing trapped air and to promote particle rearrangement to densify the mix. In the case of extrusion, the extruder may be stationary or movable. The stationary extruder pushes the mix through a channel that shapes the mixture into the desired shape and promotes rearrangement of the particles to densify the article. The article is extruded from a die within an extruder, on which the article may be cut to a desired length and stacked for curing. The moving extruder pushes the mix against a fixed stop and through a passageway that molds the mix into the desired shape. As the mix is pushed against the fixed stop, the pressure within the mix increases, the particles rearrange and the mix densifies. As more and more material is extruded, the compacted compound pushes the extruder along the extrusion machine.

In certain preferred embodiments, the step of maintaining a CO2 and water vapor atmosphere within one or more internal tubes or channels comprises/involves filling an atmosphere inside the tube or channel and/or around the outside of the tube or channel or the outside of the article; recycling the filled CO2 and/or water vapor atmosphere; removing or adding water vapor to the filled atmosphere; and heating the filled atmosphere. To achieve rapid and/or uniform curing, the number, shape, size, and configuration of the ducts and channels may be designed to increase the contact area of the CO2 and water vapor with the walls of the extruded body. Generally, as curing progresses, temperature and concentration gradients occur within the filled atmosphere and within the article itself. The gradient is identified and controlled to achieve uniform curing of the article. The CO2 and water vapor flows may also be controlled, for example, by oscillating in opposite directions as the flows pass through the internal ducts or channels and the exterior of the outer surface of the article to reverse the gradient, thereby averaging the effect of temperature and concentration gradients throughout the curing phase.

In certain preferred embodiments, the step of maintaining an atmosphere of CO2 and water vapour within one or more passageways located either within the concrete article or between a plurality of concrete articles and the enclosure or between a plurality of concrete articles and the chamber assembly comprises/involves filling the passageway and/or the exterior surrounding the concrete article with the atmosphere; recycling the filled CO2 and/or water vapor atmosphere; removing or adding water vapor to the filled atmosphere; and heating the filled atmosphere.

To achieve rapid and/or uniform curing, the number, shape, size, and configuration of the ducts and channels may be designed to increase the contact area of the CO2 and water vapor with the walls of the extruded body. Generally, as curing progresses, temperature and concentration gradients occur within the filled atmosphere and within the article itself. The gradient is identified and controlled to achieve uniform curing of the article. The CO2 and water vapor flows may also be controlled, for example, by oscillating in opposite directions as the flows pass through the internal ducts or channels and the exterior of the outer surface of the article to reverse the gradient, thereby averaging the effect of temperature and concentration gradients throughout the curing phase.

In certain preferred embodiments, the step of curing the cast or extruded body comprises/involves contacting the article with an atmosphere of CO2 and/or water vapor for a period of time.

The curing temperature and time may be adjusted depending on the desired end product, such as under an atmosphere of water and CO2, at a temperature ranging from about 20 ℃ to about 150 ℃ (e.g., from about 20 ℃ to about 140 ℃, from about 20 ℃ to about 120 ℃, from about 20 ℃ to about 100 ℃, from about 20 ℃ to about 90 ℃, from about 20 ℃ to about 80 ℃, from about 20 ℃ to about 70 ℃, from about 20 ℃ to about 60 ℃, from about 30 ℃ to about 100 ℃, from about 30 ℃ to about 90 ℃, from about 30 ℃ to about 80 ℃, from about 30 ℃ to about 70 ℃, from about 30 ℃ to about 60 ℃) for about 1 hour to about 80 hours (e.g., about 1 hour to about 70 hours, about 1 hour to about 60 hours, about 6 hours to about 80 hours, about 6 hours to about 70 hours, about 6 hours to about 60 hours, about 10 hours to about 80 hours, about 10 hours to about 70 hours, about 10 hours to about 60 hours, about 15 hours to about 60 hours, about 30 hours, or more), or a combination thereof, About 15 hours to about 50 hours to about 20 hours).

The relative humidity environment of the curing process can be adjusted to suit the desired effect. For example, the relative humidity ranges from about 10% to about 98% (e.g., from about 20% to about 98%, from about 30% to about 98%, from about 50% to about 98%, from about 80% to about 98%, from about 90% to about 98%, from about 10% to about 90%, from about 10% to about 70%, from about 10% to about 50%, from about 10% to about 40%, from about 10% to about 30%, from about 10% to about 20%), the CO2 pressure ranges from about ambient to about 100psi above ambient (e.g., from about ambient to about 90psi above ambient, from about ambient to about 80psi above ambient, from about ambient to about 70psi above ambient, from about ambient to about 60psi above ambient, from about 20psi above ambient to about 100psi above ambient, from about 30 to about 100psi above ambient, and the CO concentration ranges from about 2% to about 2% and ranges from about 10% to about 100% CO Above (e.g., from about 20% to 90%, from about 30% to 90%, from about 40% to 90%, from about 10% to 70%, from about 10% to 50%), thereby producing a composite material having a uniform, homogeneous, and porous structural appearance.

As in exemplary production in certain embodiments of the invention, the material used is ground calcium silicate. In an exemplary embodiment, the calcium silicate composition of the present invention, the ground calcium silicate particles used have a particle size such that cumulative 10% of the particle size in the volume distribution of the particle size distribution is greater than 1 μm in diameter.

The ground calcium silicate can have an average particle size of from about 1 μm to about 100 μm (e.g., from about 1 μm to about 80 μm, fromAbout 1 μm to about 60 μm, from about 1 μm to about 50 μm, from about 1 μm to about 40 μm, from about 1 μm to about 30 μm, from about 1 μm to about 20 μm, from about 1 μm to about 10 μm, from about 5 μm to about 90 μm, from about 5 μm to about 80 μm, from about 5 μm to about 70 μm, from about 5 μm to about 60 μm, from about 5 μm to about 50 μm, from about 5 μm to about 40 μm, from about 10 μm to about 80 μm, from about 10 μm to about 70 μm, from about 10 μm to about 60 μm, from about 10 μm to about 50 μm, from about 10 μm to about 40 μm, from about 10 μm to about 30 μm, from about 10 μm to about 20 μm, about 1 μm, 10 μm, 15 μm, 25 μm, 40 μm, 70 μm, 60 μm, from about 10 μm to about 10 μm, 30 μm, 80 μm, or more, 100 μm), a bulk density of from about 0.5g/mL to about 3.5g/mL (loose, e.g., 0.5g/mL, 1.0g/mL, 1.5g/mL, 2.0g/mL, 2.5g/mL, 2.8g/mL, 3.0g/mL, 3.5g/mL), and from about 1.0g/mL to about 1.2g/mL (dense), and a surface area of from about 1.5 m/mL²G to about 3.5m²G (e.g., 1.5 m)²/g、2.0m²/g、2.3m²/g、2.5m²/g、2.8m²/g、3.0m²/g、3.2m²/g、3.5m²/g).

In certain preferred embodiments, the particulate composition comprises about 10 wt.% to about 95 wt.% (e.g., about 20 wt.% to about 95 wt.%, about 30 wt.% to about 95 wt.%, about 50 wt.% to about 95 wt.%, about 60 wt.% to about 95 wt.%, about 20 wt.% to about 90 wt.%, about 20 wt.% to about 80 wt.%, about 20 wt.% to about 70 wt.%, about 30 wt.% to about 80 wt.%, about 50 wt.% to about 80 wt.%) of the ground calcium silicate material.

Chemical admixtures, such as plasticizers, retarders, catalysts, dispersants, and other rheology modifiers, can also be used in the manufacture of the discrete articles. Certain commercially available chemical admixtures, such as basf, may also be included

GleniumTM 7500 chemical and Acumer TM Dow chemical. In certain embodiments, the one or more pigments may be uniformly dispersed or substantially non-uniformly dispersed in the bonding matrix, depending on the desired composite material. The pigment can be any suitable pigment including, for example, various metal oxides (e.g., metal oxides)Black iron oxide, cobalt oxide and chromium oxide). The pigment may be any one or more colors, for example selected from black, white, blue, gray, pink, green, red, yellow and brown. The pigment may be present in any suitable amount, for example, in an amount ranging from about 0.0% to about 10% by weight, depending on the desired composite.

In certain embodiments, the one or more pigments may be uniformly dispersed or substantially non-uniformly dispersed in the bonding matrix, depending on the desired composite material. The pigment can be any suitable pigment including, for example, various metal oxides (e.g., black iron oxide, cobalt oxide, and chromium oxide). The pigment may be any one or more colors, for example selected from black, white, blue, gray, pink, green, red, yellow and brown. The pigment can be present at any suitable level, for example, in an amount ranging from about 0.0% to about 10% by weight (e.g., about 0.0% to about 8%, about 0.0% to about 6%, about 0.0% to about 5%, about 0.0% to about 4%, about 0.0% to about 3%, about 0.0% to about 2%, about 0.0% to about 1%, about 0.0% to about 0.5%, about 0.0% to about 0.3%, about 0.0% to about 2%, about 0.0% to about 0.1%) depending on the desired composite.

Thus, various combinations of curing conditions, including different reaction temperatures, pressures, and reaction times, can be designed to achieve the desired production process. In a first exemplary embodiment, water in liquid form is delivered with CO2 gas to an article that has been pre-dried in a drying oven and cured at about 90 ℃ and about 20psig (i.e., 20psig above ambient atmospheric pressure) for about 48 hours. In a second exemplary embodiment, water is retained in the precursor material (e.g., as residual water from a previous mixing step) and CO2 gas is delivered to the article and cured at about 60 ℃ and 0psig (at ambient atmospheric pressure) for about 19 hours. In a third exemplary embodiment, water in vapor form is delivered to the article with CO2 and cured at about 90 ℃ and 20psig (20 psig above ambient atmospheric pressure) for about 19 hours.

It should be noted that the properties, production time, and scale of the article can be fine tuned based on the disclosure herein, for example, by adjusting the curing process (e.g., CO2 delivery, system pressure and temperature) and the proportions and components of the mixture.

In addition to the materials used and the manufacturing process providing good environmental and economic benefits, the hollow articles of the present invention are superior in performance to many hollow articles made from conventional concrete, for example, by achieving better stability in a shorter time than is the case with precast concrete articles made using ordinary portland cement.

Bonding unit, bonding matrix, and composite material

Discussion of the chemistry

The present invention provides an apparatus and method for making novel composite materials that cure primarily through a CO2 consuming reaction. The materials exhibit beneficial properties and can be readily produced using widely available low cost precursor materials and in a process suitable for large scale production with minimal environmental impact. The precursor materials include cheap and abundant calcium silicate-rich compositions, fine particles and coarse particles. The calcium silicate composition may include a composition of milled products containing various calcium silicate phases including, for example, CS, C3S2, C2S, and calcium silicate-based amorphous phases. The fine and coarse particles may include ground limestone or other calcium carbonate-based materials, ground quartz or other SiO 2-based materials, sand, and crushed rock. The fine and coarse particles may also include crushed ores such as granite, mica, and feldspar. Other process components include water and CO 2. The physical appearance and/or mechanical properties of the resulting composite material can be fine-tuned using various additives, such as admixtures selected from one or more of pigments (e.g., black iron oxide, cobalt oxide, and chromium oxide), colored glasses, and/or colored quartz. Additives relating to the reduction of water usage and rheology modification may also be used.

As disclosed herein, the composite material may be produced by using a high efficiency energy efficient Hydrothermal Liquid Phase Sintering (HLPS) process to produce a binding unit that holds the various components of the composite material together. The composite material can be produced at low cost and with good environmental impact. For example, in a preferred embodiment of the present invention, CO2 acts as a reactant, sequestering CO2 and forming binding units in the resulting composite produced, and the carbon footprint of such a composite is incomparable with any existing production technology. The HLPS process is driven by the thermodynamic means of the free energy of chemical reactions and the reduction in surface energy (area) caused by crystal growth. Because solutions (aqueous or non-aqueous) are used instead of high melting point fluids or high temperature solid media to transport reactive species, the kinetics of the HLPS process proceed at reasonable rates at low temperatures.

Various characteristics of HLPS, calcium silicate based cements, in conjunction with carbonation and formation of the cells, apparatus and processes thereof, and discussion of related subject matter may be found in U.S. patent No. 8,114,367, U.S. publication No. US 2009/0143211 (application serial No. 12/271,566), U.S. publication No. US 2011/0104469 (application serial No. 12/984,299), U.S. publication No. 2009/0142578 (application serial No. 12/271,513), U.S. publication No. 2013/0122267 (application serial No. 13/411,218), U.S. publication No. 2012/0312194 (application serial No. 13/491,098), WO2009/102360(PCT/US2008/083606), WO2011/053598(PCT/US2010/054146), WO2011/090967(PCT/US2011/021623), U.S. provisional application No. 61/708,423 filed on 1/10/2012, and U.S. publication No. 2014/0127450 (application serial No. 14/045,758), U.S. publication No. 2015/0266778 (application serial No. 14/045,519), U.S. publication No. 2014/0127458 (application serial No. 14/045,766), U.S. publication No. 2014/0342124 (application serial No. 14/045,540), U.S. publication No. 2014/0272216 (application serial No. 14/207,413), U.S. publication No. 2014/0263683 (application serial No. 14/207,421), U.S. publication No. 2014/0314990 (application serial No. 14/207,920), U.S. patent No. 9,221,027 (application serial No. 14/209,238), U.S. publication No. 2014/0363665 (application serial No. 14/295,601), U.S. publication No. 2014/0361471 (application serial No. 14/295,402), U.S. publication No. 2016/0355439 (application serial No. 14/506,079), U.S. publication No. 2015/0225295 (application serial No., U.S. publication No. 2016/0168720 (application serial No. 14/584,249), U.S. publication No. 2015/0336852 (application serial No. 14/818,629), U.S. publication No. 2016/0031757 (application serial No. 14/817,193), U.S. publication No. 2016/0272544 (application serial No. 15/074,659), U.S. publication No. 2016/0096773 (application serial No. 14/874,350), U.S. publication No. 2016/0340261 (application serial No. 14/715,497), U.S. publication No. 2016/0272545 (application serial No. 15/074,692), U.S. publication No. 2017/0102373 (application serial No. 15/290,328), U.S. publication No. 2017/0121223 (application serial No. 15/335,520), U.S. publication No. 2017/0204010 (application serial No. 15/409,352), U.S. publication No. 2017/0253530 (application serial No. 82, U.S. publication No. 2017/0320781 (application serial No. 15/587,705), application serial No. 15/609,908 filed on 31.5.2017, application serial No. 15/716,392 filed on 26.9.2017, each of which is expressly incorporated herein by reference in its entirety for all purposes.

Fig. 1-8 show phase diagrams of different phase relationships between some of the materials described herein.

In certain preferred embodiments, the plurality of bonding elements are formed from a ground calcium silicate composition via chemical conversion using a gas-assisted HLPS process to react the ground calcium silicate composition with CO 2.

In certain embodiments, the composite is characterized by a compressive strength of from about 90MPa to about 175MPa (e.g., about 90MPa to about 150MPa, about 90MPa to about 140MPa, about 90MPa to about 130MPa, about 90MPa to about 120MPa, about 90MPa to about 110MPa, about 100MPa to about 175MPa, about 120MPa to about 175MPa, about 130MPa to about 175MPa, about 140MPa to about 175MPa, about 150MPa to about 175MPa, about 160MPa to about 175 MPa).

In certain embodiments, the composite is characterized by a flexural strength of from about 5MPa to about 30MPa (e.g., about 5MPa to about 25MPa, about 5MPa to about 20MPa, about 5MPa to about 15MPa, about 5MPa to about 10MPa, about 10MPa to about 30MPa, about 20MPa to about 30MPa, about 25MPa to about 30 MPa).

In certain embodiments, the composite is characterized by a water absorption of less than about 10% (e.g., less than 8%, 5%, 4%, 3%, 2%, or 1%).

The composite material may exhibit one or more of its desirable textures, patterns and physical properties, particularly as characteristic of natural stone. In certain preferred embodiments, the composite material exhibits a visual pattern similar to natural stone. Other characteristics include color (e.g., black, white, blue, pink, gray (light to dark gray), green, red, yellow, brown, cyan (cyan), or violet) and texture.

Discussion of instruments and Processes

CO2 control

In the illustrated embodiment, commercial grade CO2 is used, provided by various industrial gas companies (such as Praxair, inc., linde ag, Air Liquide, among others) with a purity of about 99%. Such a supply may be stored in a large pressurized storage tank in the form of liquid carbon dioxide, the temperature of which is adjusted to maintain a vapor pressure of about 300 PSIG. The gas pipe is then sent to a CO2 curing enclosure or chamber. In the simplest system, CO2 flows through the housing at a rate sufficient to displace ambient air within the housing. Generally, the purge time is based on the size of the shell and the rate at which the CO2 gas stream is supplied. In many systems, the process of purging the enclosure of air can be completed in a few minutes to bring the concentration of CO2 to a reasonable level for subsequent curing. In a simple system, CO2 gas is then fed into the system at a preset rate to maintain a sufficient CO2 concentration to drive the curing reaction.

For example, a method for maintaining carbon dioxide concentration during a reaction is now described that is well suited to maintaining a highly consistent concentration, although it is a "closed loop" process, which is often the most expensive technique. The method measures the concentration of CO2 directly in the system and controls the CO2 concentration at a set point through an electronic/automatic control valve using a controller such as a PLC. A measurement technique such as NDIR technique should preferably be employed to directly measure CO 2. In the NDIR measurement method, a gas sample stream is withdrawn from the system using a low-flow pump. A chiller is used to draw moisture from the gas stream before the NDIR instrument samples the gas. Thus, the measurement provided by the analyzer lacks the water vapor component in the gas stream and requires adjustment to account for the removal of humidity from the test sample. The humidity of the measurement system air stream may use dry-bulb-wet-bulb humidity measurement techniques, may use dry-bulb-wet-bulb humidity measurement devices, or may use different types of humidity sensors. The exact CO2 concentration can be calculated using a computer control system or PLC. Once the exact concentration of CO2 is known, the proportional control valve can be manipulated to add dry CO2 to the system when CO2 is consumed and below the set point required at that time. In various embodiments, the set point can be varied over time, if desired, based on experience with the particular composition, shape, and dimensions of the composite sample.

Humidity control

Fig. 9 is a schematic diagram of a CO2 composite curing chamber humidified according to the principles of the present invention. In fig. 9, a water source is provided and water vapor is added to the atmosphere circulating within the curing chamber. The water may be any convenient source of potable water. In certain embodiments, ordinary tap water is used. In some embodiments, the water can be converted to steam by flowing through an atomizing or misting nozzle, an electric steam generator, a gas-fired steam generator, or by heating to a temperature above the temperature of the gas in the chamber, resulting in evaporation from a liquid water source, such as a drum reactor with a submerged heater. In another embodiment, to increase the relative humidity of the incoming gas stream, a source of CO2 may be flowed into the system after being bubbled through a heated water source, for example, a drum reactor configured for "through" or "open loop" processing.

Relative humidity is an important parameter in both conventional concrete curing and CO2 composite curing. In a conventional curing chamber, there is a humid air atmosphere consisting mainly of nitrogen, oxygen and water vapor. In these systems, the relative humidity is most often measured using standard capacitive sensor technology. However, the gas atmosphere of the CO2 curing chamber mainly comprises CO2, which is not compatible with certain types of sensors. Sensing technologies such as dry-bulb-wet-bulb technology, for example, using the humidity ratio of carbon dioxide and water vapor or dipolar polarization water vapor measurement instruments or cold mirror hygrometers or capacitive humidity sensors, may be used in the CO2 composite curing system described herein.

Depending on the type and geometry of the product being cured, the design of the chamber, and the fill rate of the product in the chamber, it may be desirable to reduce or increase the humidity and adjust it to a particular set point. The set point may vary from 1% to 99% relative humidity. During curing of the CO2 composite, three different humidity control methods may exist and may be combined into one system. Fig. 9 illustrates a humidification method in one embodiment of a CO2 solidification system. Another method allows for the removal of moisture from the system to cure the composite product using CO 2. One simple way to reduce the relative humidity is to replace the moist gas in the system with a dry gas, such as carbon dioxide. In another embodiment, the relative humidity can be reduced and thus water vapor removed from the gas by a non-purging method, which in a preferred embodiment is a water extraction enabled chiller.

Fig. 10 is a schematic diagram of a curing chamber with various humidity control methods and the ability to control and replenish CO2 using constant flow or pressure regulation, and the ability to control temperature in accordance with the principles of the present invention. The system can provide closed loop control or control using feedback where the set points for the operating parameters, e.g., CO2 concentration, humidity and temperature, required at a particular time in the process cycle are provided and the actual values of these controlled parameters are determined to determine if they are the desired values. If a deviation from the desired value is measured, a corrective action is performed to bring the value of the parameter into agreement with the desired value. Such control systems can be expensive and complex, and can be useful for high value products or products requiring very precise process conditions.

Temperature control

In some embodiments, the temperature is measured using a sensor such as a thermocouple or an RTD. The measurement signal is directed back to an energy controller or computer capable of regulating the energy entering the heat exchanger, which can regulate the energy entering the heat exchanger, thereby enabling the temperature of the entire system to be adjusted over time. The blower is an important component of the heating system because it can help transfer heat energy to the gas which is in turn transferred to the product and the chamber, which itself is an important part of controlling the humidity of the sample. The heating means may be electrical or gas. The jacketed furnace can be used to control the temperature of the CO2 flowing through the chamber in contact with the heated jacket, which can use any convenient heat source. The external heating means may include, but is not limited to, electrical heating, hot water heating, or hot oil heating. Heretofore, for CO2 curing chambers that used indirect gas fired systems, the use of direct gas fired burners was avoided because direct gas fired burners would draw air and combustion products into the system, thereby diluting CO2 and making CO2 concentration control problematic. Some smaller scale systems, such as drum reactors, utilize a jacket heater rather than heating elements within the chamber to heat the entire surface of the chamber.

Airflow control

Another control parameter is the rate of gas flow through the material to be solidified in the system. The gas flow rate is highly dependent on process equipment variables including, but not limited to, chamber design, baffle design, fan size, fan speed/power, number of fans, temperature gradients within the system, rack design within the system, and sample geometry within the system. Adjusting the blower speed (RPM's) is the simplest way to control the air flow rate in the chamber, typically by a variable frequency drive to control the speed of the blower motor. A blower may be used to circulate the gas at a desired rate within the curing chamber. In the system, the airflow rate in the system is measured using a variety of different techniques, including but not limited to pitot tube measurements and laser doppler detection systems. The measurement signal of the air flow rate can be sent to a computer system or programmable controller and can be used as a control parameter in the curing situation.

Method for preparing composite material

The general process of preparing the composite material is to mix the particulate component with the liquid component to form a slurry mixture; casting the slurry mixture into a mold, pressing the slurry in a vibrating mold, extruding the slurry, slip forming the slurry, or forming the slurry mixture into a desired shape using any other forming method common in concrete production, and curing the formed slurry mixture for about 1 hour to about 80 hours under steam conditions comprising water and CO2 at a temperature ranging from about 20 ℃ to about 150 ℃, with a pressure ranging from about ambient atmospheric pressure to about 50psi above ambient atmospheric pressure, and a CO2 concentration range from about 10% to about 90%, to produce a composite exhibiting texture and/or pattern and desirable physical properties relating to compressive strength, flexural strength, density, resistance to degradation, and the like.

The particulate composition comprises a ground calcium silicate composition having an average particle size in the range of from about 1 μm to about 100 μm. In addition, the particulate composition may include ground calcium carbonate or SiO 2-containing material having an average particle size in the range of from about 3 μm to about 25 μm. The liquid composition may include water, and may also include a water-soluble dispersant.

The method may further comprise the step of drying the cast mixture prior to curing and casting the mixture. The particulate composition further comprises a pigment or colorant as described herein.

In certain embodiments, the formed slurry mixture is cured for about 1 hour to about 70 hours at a temperature ranging from about 30 ℃ to about 120 ℃, with a vapor ranging from about ambient atmospheric pressure to about 30psi above ambient atmospheric pressure and comprising water and CO 2.

In certain embodiments, the formed slurry mixture is cured for about 1 hour to about 70 hours at a temperature ranging from about 60 ℃ to about 110 ℃, with a vapor ranging from about ambient atmospheric pressure to about 30psi above ambient atmospheric pressure and comprising water and CO 2.

In certain embodiments, the formed slurry mixture is cured for about 1 hour to about 60 hours at a temperature ranging from about 80 ℃ to about 100 ℃, with a vapor comprising water and CO2 having a pressure ranging from about ambient atmospheric pressure to about 30psi above ambient atmospheric pressure.

In certain embodiments, the formed slurry mixture is cured at a temperature equal to or less than 60 ℃, under ambient atmospheric pressure, and under a vapor comprising water and CO2 for about 1 hour to about 50 hours.

For example, in certain embodiments, the ground calcium silicate composition has an average particle size of from about 1 μm to about 100 μm (e.g., about 1 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm), a bulk density of from about 0.5g/mL to about 3.5g/mL (loose, e.g., 0.5g/mL, 1.0g/mL, 1.5g/mL, 2.0g/mL, 2.5g/mL, 2.8g/mL, 3.0g/mL, 3.5g/mL) and from about 1.0g/mL to about 1.2g/mL (dense), a Blaine (Blaine) surface area of from about 150 μm²/kg to about 700m²Kg (e.g., 150 m)²/kg，200m²/kg，250m²/kg，300m²/kg，350m²/kg，400m²/kg，450m²/kg，500m²/kg，550m²/kg，600m²/kg，650m²/kg，700m²/kg)。

In certain preferred embodiments, the liquid composition comprises water and a water-soluble dispersant comprising a polymer salt (e.g., an acrylic acid homopolymer salt) at a concentration of from about 0.1% to about 2% w/w of the liquid composition.

Composites prepared according to the procedures described herein can exhibit compressive strengths of from about 3.0MP to about 30.0MPa (e.g., about 3MPa, 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa), and flexural strengths of from about 0.3MPa to about 4.0MPa (e.g., about 0.3MPa, 0.5MPa, 1.0MPa, 1.5MPa, 2.0MPa, 2.5MPa, 3.0MPa, 3.5MPa, 4.0 MPa).

Any suitable precursor material, such as the calcium silicate compositions described herein, can be used. It is believed that calcium ions leach from the calcium silicate particulate composition, converting the peripheral portion of the calcium silicate particulate composition to a calcium deficient state. As the calcium ions continue to leach from the peripheral portion of the particle, the structure of the peripheral portion eventually becomes unstable and decomposes, thereby converting the calcium-deficient peripheral portion of the particle into a first layer that is predominantly rich in silica. At the same time, a second layer, mainly calcium carbonate, precipitates out of the water. An example of such a three-layer structure is shown in fig. 13, reprinted from U.S. publication No. 2013/0122267a1 (fig. 6(a) -6(c)), showing an example of energy dispersive x-ray spectroscopy (EDS) chemical mapping of an exemplary bound matrix, and illustrating the superposition of silicon (fig. 13a) and calcium (fig. 13b) maps. In FIG. 13c, the CaSiO2, SiO2, and CaCO3 regions are indicated by arrows. Wollastonite (CaSiO3) core particles are surrounded by SiO2 rich regions and by CaCO3 particles. The different elements of the bonding matrix are held together by the CaCO3 particles. The XRD pattern of such compositions shows that CaSiO3 and CaCO3 (calcite) are crystalline phases, while the silicon-rich regions are amorphous.

The terms "coarse" and "fine" filler particles as used herein refer to any suitable material having a suitable particle size and particle size distribution. For example, in certain preferred embodiments, the filler particles are made from a calcium carbonate-rich material such as limestone (e.g., ground limestone). In certain materials, the filler particles are made of one or more silica-based or silicate-based materials such as quartz, mica, granite, and feldspar (e.g., ground quartz, ground mica, ground granite, and ground feldspar), among others.

In certain embodiments, the filler particles may include natural, synthetic, and recyclable materials, such as glass, recyclable glass, coal slag, fly ash, calcium carbonate rich materials, and magnesium carbonate rich materials.

In certain embodiments, the average particle size of the "coarse" and "fine" filler particles is in the range of from about 5 μm to about 7 μm (e.g., about 5 μm)_iTm to about 5mm, about 5_i-tm to about 4mm, about 5 μm to about 3mm, about 5 μm to about 2mm, about 5 μm to about 1mm, about 5 μm to about 500 μm, about 5 μm to about 300 μm, about 20 μm to about 5mm, about 20 μm to about 4mm, about 20 μm to about 3mm, about 20 μm to about 2mm, about 20 μm to about 1mm, about 20 μm to about 500 μm, about 20 μm to about 300 μm, about 100 μm to about 5mm, about 100 μm to about 4mm, about 100 μm to about 3mm, about 100 μm to about 2mm, about 100 μm to about 1 mm.

In certain embodiments, the weight ratio of the binding units to the "coarse" and "fine" filler particles may be any suitable ratio, depending on the intended application of the composite product. For example, the weight ratio of binding units to "coarse" and "fine" filler particles may range from about (50 to 99): in the range of about (1 to 50), for example, from about (60 to 99): about (1 to 40), about (80 to 99): about (1 to 20), about (90 to 99): about (1 to 10), about (50 to 90): about (10 to 50), about (50 to 70): about (30 to 50). In certain embodiments according to the application, the weight ratio of binding units to filler particles may range from about (10 to 50): a range of about (50 to 90), e.g., about (30 to 50): about (50 to 70), about (40 to 50): about (50 to 60).

More specifically, the first and second layers can be formed from precursor particles according to the following reaction (1-3), wherein water can be used as a reaction medium rather than a reactant (i.e., water is not consumed):

CaSiO3(s)+CO2(g)→CaCO3(s)+SiO2(s) (1)

Ca3Si2O7(s)+3CO2(g)→3CaCO3(s)+2SiO2(s) (2)

Ca2SiO4(s)+2CO2(g)→2CaCO3(s)+SiO2(s) (3)

for example, in a silicate mineral carbonation reaction such as occurs with calcium silicate compositions, gaseous CO2 is introduced, which is dissolved in a permeate such as water. The CO2 dissolves the acidic carbonates formed (e.g., carbonic acid, H2CO3), resulting in a decrease in the pH of the solution, the weakly acidic solution non-uniformly dissolving calcium species from the calcium carbonate phase. Calcium can be filtered out of the calcium-containing amorphous phase by a similar mechanism. The released calcium ions and dissociated carbonates cause insoluble carbonate precipitates. The silica-rich layer is believed to be a calcium depleted layer that remains on the mineral particles.

Thus, according to a preferred embodiment of the present invention, CO2 preferentially reacts with calcium ions of the precursor core of the calcium silicate composition, thereby converting the peripheral portion of the precursor core into a silica-rich first layer and a calcium silicate-rich second layer. Additionally, the first and second layers are present on the core as a barrier to further reaction between the calcium silicate and the carbon dioxide, thereby producing a bonded unit having a core, the first layer and the second layer.

In certain embodiments, silicate materials containing metals other than or in addition to Ca, for example, forsterite (Mg2SiO4), diopside (CaMgSi2O6), and talc (Mg3Si4O10(OH)2)), can react with carbon dioxide dissolved in water in a similar manner to the calcium silicate reaction described above. Such silicate materials can be used as precursors for the bonding element, alone, in combination and/or in combination with the calcium silicate composition, in accordance with the principles of the present invention.

Preferably, the gas-assisted HLPS process uses partially infiltrated pore space to achieve gas diffusion, thereby enabling rapid infiltration of the porous preform and saturation of the pores with a thin film of liquid interfacial solvent by dissolved CO 2. The solubility of the CO 2-based substance in pure water was low (1.5 g/L at 25 ℃ under 1 atmosphere). Therefore, a large supply of CO2 must be continuously supplied to the porous preform and CO2 distributed throughout the porous preform to achieve significant carbonate conversion. The use of gas phase diffusion may provide a greatly increased (about 100 times) diffusion length compared to the diffusion length for the same time that soluble CO2 diffuses in the liquid phase. (Handbook of chemistry and Physics, Editor: D.R. Lyder, Chapter 6, 8, 2006 nd edition 2006-2007, CRC.) ("Handbook of chemistry and Physics", Editor: D.R. Lide, Chapters 6and 8,87^thEdition 2006-2007, CRC.) this partially saturated state enables the reaction to proceed to a high degree of carbonation within a fixed period of time.

The liquid water in the pores accelerates the reaction rate because the liquid water provides a medium for ionizing the carbonic acid and calcium species. However, the water level needs to be low enough to allow the CO2 gas to diffuse into the porous matrix before dissolving in the pore-bound aqueous phase. Further, the actively dissolved porous preform serves as a template for the growth of the expanded reaction crystal, and thus, a bonding unit and a matrix having minimal deformation and residual stress can be formed. This results in large, complex shapes, such as those required in infrastructure and building materials, as well as many other applications.

Thus, different combinations of curing conditions can be designed to achieve the desired production process, including different reaction temperatures, pressures, and reaction times. In a first embodiment, water is present in the precursor material (e.g., as residual water from a previous mixing step), and liquid water is provided to the precursor material along with CO2 (e.g., to maintain a water level and/or to control evaporative loss of water), and curing is carried out at about 90 ℃ and about 20psig (i.e., 20psi above ambient atmospheric pressure) for a time from about 2 hours to about 90 hours.

In a second embodiment, water is present in the precursor material (e.g., as residual water from a previous mixing step), and water vapor is supplied to the precursor material along with CO2 (e.g., to maintain a water level and/or to control evaporative loss of water) and cured at about 90 ℃ and about 20psig (i.e., 20psi above ambient atmospheric pressure) for a time period of from about 2 hours to about 90 hours.

In a third embodiment, water is present in the precursor material (e.g., as residual water from a previous mixing step), and water vapor is supplied to the precursor material along with CO2 (e.g., to maintain a water level and/or control evaporative loss of water) and cured at about 25 ℃ to about 90 ℃ and 0psig (i.e., ambient atmospheric pressure) for about 2 hours to about 72 hours.

In the above examples, the time required to cure the composite article is based on the ability of water vapor and CO2 gas to diffuse through the article. Generally, thicker articles require longer curing times than thinner articles. Similarly, a high density article (less open pore space) will require a longer cure time than a low density article (more open pore space). The following table provides examples of how the curing time may vary with respect to the three-dimensional minimum thickness (or wall thickness or cross-sectional thickness) and the bulk density of the manufactured object.

TABLE 1 examples of curing times and minimum thicknesses

Discussion of the microstructure produced

As shown in fig. 11(a) -11(c), the bonding unit includes a core (represented by a black inner portion), a first layer (represented by a white middle portion), and a second layer or encapsulation layer (represented by an outer portion). The first layer may comprise only one or more sub-layers and may completely or partially cover the core. The first layer may be present as a crystalline phase, an amorphous phase, or a mixture thereof, and be in the form of a continuous phase or discrete particles. The second layer may comprise only one or more sub-layers and may also completely or partially cover the first layer. The second layer may include a plurality of particles or may be a continuous phase and have a minimum of discrete particles.

The binding units may take on any size, any regular or irregular, solid or hollow morphology, depending on the intended application. Exemplary morphologies include cubic, rectangular, prismatic, disk, pyramidal, polyhedral or multifaceted particles, cylinders, spheres, cones, rings, tubes, crescent, needles, fibers, filaments, flakes, spheres, sub-spheres, beads, grapes, granules, ovals, rods, corrugations, and the like.

Generally, as discussed in more detail herein, bound units are produced from active precursor materials (e.g., precursor particles) by a conversion process. The precursor particles can be of any size and shape as long as the requirements of the intended application are met. The conversion process will generally produce bound units having a similar size and shape as the precursor particles.

Within the binding matrix, the binding units can be placed relative to each other in any of several orientations. Fig. 12(a) -12(f) show an exemplary bonding matrix comprising fibrous or sheet-like bonding elements in different orientations that are diluted with an incorporated filler material, as indicated by the spacing between the bonding elements. For example, fig. 12(a) shows a binding matrix comprising fibrous binding units arranged in a unidirectional ("1-D") orientation (e.g., arranged relative to the x-direction). Figure 12(b) shows a binding matrix comprising sheet-like binding units arranged in a bi-directional ("2-D") orientation (e.g., arranged with respect to the x and y directions). Figure 12(c) shows a binding matrix comprising sheet-like binding units arranged in a three-dimensional ("3-D") orientation (e.g., arranged relative to the x, y, and z directions). FIG. 12(d) shows a binding matrix comprising plate-like binding units in random orientation, wherein the binding is not aligned with respect to any particular direction. FIG. 12(e) shows a binding matrix comprising a relatively high concentration of plate-like binding units arranged in a 3-D orientation. FIG. 12(f) shows a binding matrix comprising a relatively low concentration of sheet-like binding units (percolation network) in random orientations. The composite of fig. 12(f) reached the percolation threshold because most of the bonding units were in contact with each other, forming a continuous network of contacts from one end of the material to the other. The percolation threshold is the critical concentration above which the binding units exhibit long range connectivity, with either an ordered orientation, e.g., fig. 12(e), or a random orientation, e.g., fig. 12 (f). Examples of Connectivity patterns can be found, for example, in Nenam et al, "Connectivity and piezoelectric-pyroelectric composites", materials research bulletin, Vol.13, p.525-536,1978 (Newnham, et al, "Connectivity and piezoelectric-pyroelectric composites", mat. Res. Bull. Vol.13, pp.525-536,1978).

The plurality of binding units can be obtained from any suitable precursor material by chemical conversion, for example, from any suitable calcium silicate composition precursor. The precursor calcium silicate composition may include one or more chemical elements of aluminum, magnesium and iron.

The plurality of binding units may have any suitable average particle size and particle size distribution, depending on the desired composite material. In certain embodiments, the plurality of binding units have a mean particle size in a range from about 1 μm to about 100 μm (e.g., from about 1 μm to about 80 μm, from about 1 μm to about 60 μm, from about 1 μm to about 50 μm, from about 1 μm to about 40 μm, from about 1 μm to about 30 μm, from about 1 μm to about 20 μm, from about 1 μm to about 10 μm, from about 5 μm to about 90 μm, from about 5 μm to about 80 μm, from about 5 μm to about 70 μm, from about 5 μm to about 60 μm, from about 5 μm to about 50 μm, from about 5 μm to about 40 μm, from about 10 μm to about 80 μm, from about 10 μm to about 70 μm, from about 10 μm to about 60 μm, from about 10 μm to about 50 μm, from about 10 μm to about 40 μm, from about 10 μm to about 30 μm, from about 10 μm to about 20 μm).

In some cases, the composite material includes a plurality of binding units and a plurality of filler particles. Each bonding element comprises a core consisting essentially of a calcium silicate composition, a first or inner layer rich in silica, and a second or outer layer rich in calcium carbonate. The plurality of binding units and the plurality of filler particles together form one or more binding matrices, and the binding units and the filler particles are sufficiently uniformly dispersed and bound together such that the composite exhibits one or more of texture, pattern, and physical properties. In some cases, the binding unit may have a magnesium silicate core, a first or inner layer rich in silica, and a second or outer layer rich in magnesium carbonate. The magnesium carbonate may include oxides of aluminum, calcium, iron, or manganese.

In certain embodiments, these composites may exhibit various patterns, textures, and other characteristics, such as visual patterns of various colors. In addition, the composite material of the present invention exhibits compressive strength, flexural strength and water absorption similar to those of conventional concrete or similar natural materials.

In certain embodiments, the composite further comprises a pigment. Depending on the desired composite material, the pigment may be uniformly dispersed or significantly non-uniformly dispersed in the bonding matrix. The pigment can be any suitable pigment, such as oxides of various metals (e.g., iron oxide, cobalt oxide, chromium oxide). The pigment may be of any color or colors, for example selected from black, white, blue, gray, pink, green, red, yellow and brown. The pigment can be present in any suitable amount, such as in an amount ranging from about 0.0 wt% to about 10 wt% by weight (e.g., about 0.0 wt% to about 8 wt%, about 0.0 wt% to about 6 wt%, about 0.0 wt% to about 5 wt%, about 0.0 wt% to about 4 wt%, about 0.0 wt% to about 3 wt%, about 0.0 wt% to about 2 wt%, about 0.0 wt% to about 1 wt%, about 0.0 wt% to about 0.5 wt%, about 0.0 wt% to about 0.3 wt%, about 0.0 wt% to about 2 wt%, about 0.0 wt% to about 0.1 wt%) depending on the desired composite.

Examples

EXAMPLE 1 curing System with Adjustable Pitch Chamber Assembly

A curing system is manufactured in which the spacing between the product plates can be adjusted. Increasing or decreasing the spacing between the plates on which the discrete concrete items are placed may change the size of the channel 101 formed between the top of the discrete concrete items and the bottom of the plate above the discrete concrete items. The size of the channels 101 is controlled by the spacing between the plates and the size of the discrete concrete items, affecting the velocity of the fluid through the items. For a constant volume of fluid flow between the plates, the smaller channels 101 increase the flow rate and the wider channels 101 decrease the flow rate.

Depending on the ratio of binding elements to filler, the moisture content of the uncured discrete concrete article, the degree of compaction, and the size of the discrete concrete article, the rate of fluid flow can be varied by increasing or decreasing the size of the channels 101. An image of this system is shown in fig. 15.

In some embodiments, the ratio of the bonding unit to the filler is higher, which can improve the properties of the finished product and optimize the overall process time requirements by increasing the size of the channels 101.

In some embodiments, the lower ratio of bonding units to filler may be achieved by reducing the size of the channels 101 to improve the properties of the finished product and optimize the overall process time requirements.

In some embodiments, multiple classes of discrete concrete articles having different binding unit to filler ratios, moisture content, compaction levels, or sizes are processed within the same chamber or enclosure. In this embodiment, the size of the channel 101 may be adjusted independently for each product panel, depending on the type of article adjacent to the channel. This method allows the velocity of the process gas to be adjusted according to the optimum velocity for each concrete article to unify the characteristics of the finished product and optimize the overall process time requirements.

Example 2: curing system with reversible flow

A curing system is designed in which the process gas flows to the passages between the discrete concrete items and the chamber assembly. The flow direction between the two channels is reversible. In a housing or cavity capable of containing a plurality of discrete concrete articles arranged in an array of fluids flowing through the concrete articles, the state of the fluids, such as temperature, relative humidity or water content, changes as the fluids flow through the plurality of discrete concrete articles. After flowing through a prescribed length, which is controlled by the initial conditions of the fluid and the characteristics of the plurality of discrete concrete articles, such as the ratio of binding elements to filler, the water content, the degree of compaction, and the size, the fluid conditions in the passages between the discrete concrete articles and the chamber assembly become unsuitable for optimal curing. In other words, the temperature of the fluid drops and the relative humidity or moisture content increases beyond a threshold suitable for curing the discrete concrete article.

In some embodiments, a fluid is considered unsuitable for use when its temperature falls below 60 ℃, or below 55 ℃, or below 50 ℃, or below 45 ℃, or below 40 ℃, or below 35 ℃, or below 30 ℃ or below 25 ℃.

In some embodiments, a fluid is considered unsuitable for curing when its moisture content (expressed as relative humidity) is greater than 20%, or greater than 30%, or greater than 40%, or greater than 50%, or greater than 60%, or greater than 70%, or greater than 80%, or greater than 90%.

However, by reversing the fluid flow direction at least once during the curing cycle, the length of the array of curable discrete concrete articles can be increased. During this process, discrete concrete articles located downstream and exposed to a lower temperature and higher moisture environment are now exposed to the dryer and lower moisture fluid for at least a portion of the curing cycle. In some embodiments, the length may be increased to a double length at which the gas conditions become unsuitable for curing arranged to flow in a single stream throughout the entire curing cycle. In general, this theory is beneficial for increasing the capacity of the enclosure or chamber.

Fig. 16 shows a large scale schematic of the system. Fig. 17 shows a schematic view of the closure of the mentioned system containing the concrete object.

In another embodiment, the products may be stacked on plates above each other as shown in fig. 15 and contained inside a modified version of the system mentioned in fig. 16 and 17, in which the height of the chamber is increased to accommodate a plurality of shelves.

Example 3: curing hollow slabs using desorption isothermal method

Mixing

The components of the concrete mix design were mixed using a Sicoma TO8 series planetary mixer (model MP 250/375 WWWSW). The planetary speed was 18.5 RPM. The filler material in the form of 293.8kg of 1/4 "aggregate and 160.3kg of sand was dry mixed for 90 seconds. 5kg of water, 168g of Glenium7500(BASF) and 120g of air entraining additive were added to the dry mixture and the composition was mixed for an additional 90 seconds. 80.1kg of a binder in the form of soridia cement (soridia technology) (4% wollastonite, 19% wollastonite, 13% xonotlite, 2% calcite and 62% amorphous oxide) was added together with an additional 16kg of water to the wet mass in the mixer and the composition was mixed for a further 90 seconds. The final moisture content of the mixture was 3.68% as measured with a Sartorius MA100 moisture analyzer. A total of three batches of these batch materials were transferred to an extruder to extrude hollow slabs.

Extruding:

two 40' long 3/8 "diameter steel wire cables (low slack 7-wire, Sumidwire Products chop.) were run along the length of the steel extrusion bed to an extension of 3". The cables are placed in such a way that one is placed symmetrically between the bottom of the slab and the

cores

1 and 2 and the other between the bottom of the slab and the

cores

5 and 6.

The hollow slab was extruded on a steel bed by a commercial Alley Keyed (Elematic) EL 600/8 extruder using a screw speed of 55 RPM. The extruded slab was 18 feet long by 4 feet wide by 8 inches high and contained 6 (6 "diameter) hollow cores. Adjacent cores are separated by a 1.25 "thick wall. Figure 18 shows a picture of a hollow slab.

Curing

Fig. 19 shows a schematic view of a curing apparatus. During the curing process, the bed is heated by circulating hot water through the tubes of the steel bed. The temperature of the hot water was maintained by maintaining the temperature of the gas boiler at 81 ℃. The temperature of the top surface of the steel bed was approximately 49 deg.c. Cold water from the refrigerant (maintained at 10 c) is circulated in the condenser to remove moisture from the circulating gas stream. The electric heater (3.75kw) was maintained at 87 ℃ to heat the dry recycle gas stream before returning to the curing chamber. The speed of the recycle blower is controlled by a variable frequency drive. The initial speed of the blower was 30 Hz. Dry CO2 was supplied to the curing system as needed by an elicate (Alicat) mass flow controller. The curing chamber comprised a steel extruded bed and polyethylene sheet used as a top cover and to separate the CO2/H2O gas stream from the ambient atmosphere. The caps cover the hollow blank and are stretched between the support walls at each end of the blank. The top lid was sealed to the end wall along the steel extrusion bed using magnetic strips and inflated by a circulating gas stream. The pressure differential between the inside and outside of the cap was maintained slightly above atmospheric pressure (differential pressure +0.2 inches of water). Each end wall in the curing chamber has the same cross-section as the slab except for a slab with a wall height of 9.25 "instead of 8". Each end wall is used as the front end of a rectangular box forming a chamber with one gas inlet facing 6 holes through which gas enters or exits the curing chamber. The 6 holes are covered with a porous metal sheet so that the end chamber acts as a plenum for dispersing and moderating the gas flow into the curing chamber. One of the two ports of the differential pressure transmitter is inserted into the curing chamber through one end wall and the other port is open to the ambient atmosphere. A sampling probe of an NDIR CO2 gauge was inserted through the end wall at the other end of the curing chamber to monitor the CO2 concentration within the curing chamber throughout the curing process. Two visalas (Vaisala) humidity/temperature probes were placed in the curing chamber, one at each end just inside the end wall.

The curing chamber was purged with CO2 for 10 min. During the curing process, the gas cycle is reversed every 60 minutes. The blower speed was reduced to 15Hz as curing proceeded to 90min, then increased to 45Hz as curing proceeded to 209min and held on until curing proceeded to the end of 490 min.

Fig. 20 shows the chamber humidity measured at the end wall by a visala (Vaisala) sensor throughout the curing process, and the cumulative amount of condensate collected throughout the run.

The strength of the hollow slab was estimated at 44 points on the upper surface of the slab using a rebound hammer, which indicated an average compressive strength of 30 MPa.

Example 4: solidifying hollow castings using adsorption isotherm method

Mixing

The batch design consists of six solid components: (1) 3/8' aggregate, 29%; (2) 1/4' aggregate, 15%; (3)2mm crushed quartz, 12%; (4) 20% of building sand; (5) 200% of marble white and 13% of NYCO 400 wollastonite. The components were "dry" mixed for 2 minutes in a Kercher Industries (Kercher Industries)12 "laboratory grade mixer. Water (570g) containing the colloidal additive was added to the dry ingredients and the resulting mixture was mixed for an additional 4 minutes. More water (265g) was added and the mixture was mixed for an additional 4 minutes. Finally, water (260g) was added again and the mixture was mixed for an additional 2 minutes.

Casting of

The wet mixture was cast into a 4 "x 4" x 20 "rectangular mold with its long sides lying horizontally. A length of pvc tubing 2 "diameter x 20" wrapped in waxed paper was fixed in the centre of the mould, thereby forming a2 "diameter centre along the length of the casting. The concrete mixture was cast in 6 layers, each layer vibrated for 30 seconds and the last layer vibrated for 60 seconds.

Drying

The hollow castings were slowly dried to prevent cracking. It was air-dried overnight, then placed in a drying cabinet at 90 ℃ for 51 hours and then dried at 100 ℃ for 20 hours. After drying, the hollow casting was removed from its mold and the pvc pipe was removed from the center of the casting. The net weight of the hollow cast was 8769 grams.

Curing

Fig. 21 is a picture of the curing setting. In each end of the core, a PVC pipe is inserted, into which pipe a pipe fitting is screwed, so that the solidification gas can pass through the casting. The hollow casting was wrapped with a1 "thick aluminum foil backed fiberglass insulation. One of the pipe joints (inlet pipe assembly) of the core was connected to a gas saturator (heating vessel containing water) using 1/4' stainless steel pipe. The other tube fitting (outlet tube set) of the core was attached to the 1/4' plastic tube leading to the vent. Each tube assembly is equipped with a thermocouple so that the temperature of the curing gas can be measured before and after passage through the core. Each tube assembly is insulated using fiberglass insulation.

The water temperature in the saturator was maintained at 65 ℃ throughout the curing process. Carbon dioxide gas was bubbled through the water at a rate of 6.5 liters/minute, saturated with water vapor in the gas stream. All the heat and water used for the curing reaction is carried into the hollow core by the saturated carbon dioxide gas stream. The temperature at the core inlet rose from 26 ℃ to 60 ℃ in one hour and was maintained at 60 ℃ for the remainder of the curing process. After another 90 minutes, the temperature at the core exit rose to 53 ℃ and remained constant for the remainder of the curing time. After 20 hours, the curing process was terminated.

The insulation surrounding the hollow castings during solidification is removed and the first third (inlet end) of the castings appears to be more wet and darker in appearance than the remainder of the castings, which appear lighter in color and dry (fig. 22). The casting was completely dried in an oven until a constant weight of 8939 grams, which increased 170 grams due to carbonation. The average carbonation was 40% based on weight gain.

The dried hollow casting was cut in half to assess the uniformity of solidification, as the two ends of the casting were visually different. When the casting is cut, some material is shed from the cut and some material is shed due to the peeling of the outer edges of the cut by the saw blade. The pattern of shedding is symmetrical and the losses in both parts are about the same, so the cutting losses are about the same for both castings. The total weight of the cutting loss was 137 grams.

The inside edge (e.g., core surface) was cut very cleanly, indicating that the reaction proceeded better on the inside of the casting than on the outside, with the degree of reaction varying radially around the core. The inlet half of the dried casting weighed 4429 grams, while the outlet half of the dried casting weighed 4373 grams. The mass remaining after cutting the slab is therefore distributed uniformly in the two halves (50.3% at the inlet end and 49.7% at the outlet end). The degree of carbonation is therefore evenly distributed along the length of the hollow casting.

Applicants' disclosure is described in preferred embodiments with reference to the drawings, wherein like numerals represent the same or similar elements. Reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

The described features, structures, or characteristics of applicants' disclosure may be combined in any suitable manner in one or more embodiments. In the description herein, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that applicants' composition and/or method can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

In this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Although any methods and materials similar or equivalent to those disclosed herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are described herein. The methods described herein may be performed in any order that is logically feasible, apart from the specific order disclosed.

Is incorporated by reference

In this disclosure, reference has been made to and citations of other documents, such as patents, patent applications, patent publications, periodicals, books, papers, web content. All of these documents are incorporated herein by reference in their entirety for all purposes. Any material, or portion thereof, that is said to be incorporated by reference herein, to the extent it conflicts with existing definitions, statements, or other disclosure material set forth explicitly herein, is only incorporated to the extent that no conflict arises between that incorporated material and the material of the present disclosure, in the event that conflict arises, an embodiment that facilitates the present disclosure is resolved as the preferred disclosure.

Equality of nature

The representative examples disclosed herein are intended to aid in the description of the invention and are not intended, nor should they be construed, to limit the scope of the invention. Various modifications of the invention, in addition to those described and illustrated herein, as well as many other embodiments thereof, will be apparent to those skilled in the art from the entire contents of this document and the examples that follow, and the scientific and patent literature referred to herein. These latter embodiments, as well as their various implementations and equivalents, contain important additional information, exemplifications and guidance which can be adapted to the practice of this invention.

Claims

1. An article comprising a composite material dispersed as a plurality of discrete concrete articles; wherein one or more pipes or channels are provided between or through the plurality of discrete concrete articles to form a fluid transport system within and/or with the exterior of the plurality of discrete articles, wherein the composite material comprises:

a plurality of binding units, wherein each binding unit comprises:

mainly comprises a core of calcium silicate and a core of calcium silicate,

a first or inner silica-rich layer, and

a second or outer layer rich in calcium carbonate; and

filler particles comprising coarse filler particles and/or fine filler particles, wherein

The plurality of binding units and the plurality of filler particles together constitute one or more binding matrices in which the binding units and the filler particles are uniformly dispersed and bound together.

2. The article of claim 1, wherein

The plurality of discrete concrete items are placed in a housing or chamber.

3. The article of claim 1, wherein

Each of the plurality of discrete concrete articles includes one or more reinforcing elements embedded therein.

4. The article of claim 3, wherein

The one or more reinforcing ingredients are selected from the group consisting of rods, wires, and cables.

5. The article of claim 4, wherein

The one or more reinforcing rods are made of iron, steel, polymeric material, glass, or a combination thereof.

6. The article of claim 1, wherein

The plurality of discrete concrete articles do not include a reinforcing component embedded therein.

7. The article of any one of claims 1-6, wherein

The plurality of binding units are derived from a ground calcium silicate composition comprising one or more of natural or synthetic wollastonite, gehlenite, monetite, and amorphous phases.

8. The article of any one of claims 1-7, wherein

The plurality of bonding units are prepared by chemical conversion of calcium silicate by reacting with CO2 through a controlled hydrothermal liquid phase sintering process.

9. The article of any one of claims 1-8, wherein

The plurality of binding units are made from a precursor calcium silicate other than synthetic wollastonite or pseudo-wollastonite by chemical conversion.

10. The article of any one of claims 1-9, wherein

The weight ratio of binding units to filler particles is about 1: 5.

11. The article of manufacture of any one of claims 1-10,

the article has a water absorption of less than about 10%.

12. The article of any one of claims 1-11, wherein

The fluid transport system is adapted to flow a gas through the one or more conduits or channels and outside of the plurality of discrete articles.

13. The article of claim 12, wherein

The gas comprises carbon dioxide.

14. The article of claim 12, wherein

Fluid flowing through the one or more conduits or channels and outside of the plurality of discrete articles alters the direction of flow at least once.

15. The article of claim 12, wherein

Fluid flowing through the one or more conduits or channels and exterior of the plurality of discrete articles alters the flow rate at least once.

16. The article of any one of claims 1-15, wherein

The fluid transport system located within the exterior of the plurality of discrete articles includes between housings or chambers or chamber components within the housings or chambers.

17. A system for manufacturing an article of manufacture, comprising,

a closed housing or chamber, which is,

a composite material dispersed into a plurality of discrete concrete articles; wherein the content of the first and second substances,

providing one or more pipes or channels between or through the plurality of discrete concrete items, forming a fluid transport system inside the one or more pipes and channels and outside of the plurality of discrete items;

optionally, one or more panels on which the plurality of discrete concrete items are placed;

one or more shelves, tarpaulins, walls or panels having curved, planar, convex or concave surfaces forming one or more ducts or channels to facilitate fluid flow conditions in the fluid delivery system.

18. The system of claim 17, comprising

A fluid dispensing assembly for controlling fluid flow conditions of at least a portion of the housing or chamber.

19. The system of claim 17, comprising

A fluid distribution assembly for controlling fluid flow conditions throughout the housing or chamber.

20. The system of claim 19, wherein

The fluid distribution assembly, which controls the fluid flow conditions throughout the housing or chamber, changes the direction of the airflow at least once.

21. The system of claim 19, wherein

The fluid dispensing assembly, which controls the fluid flow conditions throughout the housing or chamber, varies the rate of airflow at least once.

22. A system as claimed in any one of claims 17 to 21, wherein

The fluid distribution assembly includes one or more fluid inlets, outlets, plenums, or perforated plates, or a combination thereof.

23. A system as claimed in any one of claims 17 to 22, wherein

The housing or chamber is made of a material selected from the group consisting of a metal, an alloy, a plastic, a polymer matrix composite, a ceramic composite, or a combination thereof.

24. A system as claimed in any one of claims 17 to 22, wherein

The housing or chamber is made of a concrete material, or steel, or tarpaulin, or a combination thereof.

25. A process for producing a manufactured article, comprising:

mixing the particulate component and the liquid component to form a mixture;

producing a cast or extruded or otherwise formed green body comprising a plurality of discrete concrete articles by casting or extrusion or other processing methods that form a mixture in a mold; wherein

Providing one or more conduits or channels between the plurality of discrete concrete items or through the plurality of discrete concrete items and the exterior of the plurality of discrete items;

maintaining a CO2 and/or water vapor atmosphere in the one or more internal conduits or channels and the exterior of the plurality of discrete materials; and

curing the plurality of discrete articles for about 1 hour to about 80 hours under an atmosphere of water and/or CO2 at a temperature ranging from about 20 ℃ to about 150 ℃, at a pressure ranging from ambient atmospheric pressure to about 60psi above ambient atmospheric pressure, and at a concentration of CO2 ranging from about 10% to about 90%.

26. The process of claim 25 wherein

Maintaining a CO2 and/or water vapor atmosphere outside of one or more internal ducts or channels and/or the plurality of discrete articles comprises:

filling an atmosphere in the exterior of the one or more internal channels and/or the plurality of discrete articles;

recycling the filled CO2 and/or water vapor atmosphere; transferring or adding water vapor to the filled atmosphere; and

the filled atmosphere is heated.

27. The process of claim 25 or 26, wherein

Maintaining a CO2 and/or water vapor atmosphere in one or more internal conduits or channels includes changing the direction or velocity of the CO2 and/or water vapor stream at least once during curing of the body.

28. The process of any one of claims 25 to 27 wherein

The particulate composition comprises ground calcium silicate comprising one or more of natural or synthetic wollastonite, pseudo-wollastonite, gehlenite, dicalcium silicate and tricalcite silicate, the ground calcium silicate having an average particle size in the range of from about 1 μm to about 100 μm, and

the liquid component includes water.

29. The process of any one of claims 25 to 28 wherein

The as-cast mixture is cured at a temperature of 60 ℃ or less, a vapor atmosphere comprising water and CO2, at ambient atmospheric pressure, for about 10 to about 50 hours.

30. The process of any one of claims 25 to 29 wherein

The ground calcium silicate is substantially ground wollastonite.

31. The process of any one of claims 25-29, further comprising

Embedding one or more reinforcing components in the mixture.

32. The process of claim 31 wherein

33. The process of claim 32, wherein

The one or more reinforcing bars are made of iron, steel, polymeric material, glass, or a combination thereof.

34. An article made by the process of any one of claims 25-33.

35. The article of claim 34, selected from the group consisting of paving materials, masonry blocks, roofing tiles, hollow slab, precast concrete articles with or without reinforcement elements.