RU2795134C2 - Control of setting time of geopolymer compositions containing reactive aluminosilicate materials characterized by high ca content - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: geopolymer composition, characterized by controlled setting time, contains: at least one reactive aluminosilicate; at least one solution of the moderator in water; at least one alkaline silicate activator solution. At least one moderator is a soluble metal salt that hydrolyses in an alkaline solution and co-precipitates the silicate components present in the alkaline silicate activator solution and is selected from the following group: anhydrous barium chloride, barium chloride dihydrate, barium nitrate, barium nitrite and barium metaborate monohydrate. At least one said retarder solution is combined with at least one said alkaline silicate activator solution prior to mixing with at least one said reactive aluminosilicate. At least one specified retarder is used in an amount of from 0.5 to 10% by weight when calculating the weight of the binder.

EFFECT: controlling the setting time of geopolymer materials for the possibility of transportation and laying.

24 cl, 2 dwg, 4 tbl, 21 ex

Description

The field of technology to which the invention belongs

The disclosed invention generally relates to additives for geopolymer compositions. More specifically, it relates to retardants for effective set control in geopolymer compositions and systems that can be used for specific applications.

State of the art

In general, geopolymers made using certain reactive aluminosilicates having a high Ca content set and harden very quickly due to the instantaneous formation of calcium silicate hydrate and calcium aluminosilicate hydrate gels. In engineering practice, geopolymers should have reasonably long setting times. This means that concrete or mortar produced using a pozzolanic binder must have a setting time long enough to allow transport and installation. However, if the setting time is too long, this becomes uneconomical. Thus, for the successful applications of geopolymer materials in the construction industry, the keys to improving proper setting time management when using a retarder.

The essence of the invention

According to a first broad aspect, the present disclosure provides a controlled set time geopolymer composition comprising: at least one reactive aluminosilicate; at least one retarder solution in water and at least one alkaline silicate activator solution, wherein at least one retarder is a soluble metal salt that hydrolyzes in the alkaline solution and coprecipitates the silicate components present in the alkaline silicate activator solution wherein said at least one retarder solution is combined with said at least one alkaline silicate activator solution prior to mixing with said at least one reactive aluminosilicate, said at least one retarder being selected from the group: anhydrous barium chloride, chloride dihydrate barium, barium nitrate, barium nitrite and barium metaborate monohydrate, wherein said at least one moderator is used in an amount in the range of 0.5 to 10% by weight based on the weight of the binder.

According to a second broad aspect, the present disclosure provides a process for preparing a geopolymer composition having a controlled set time, comprising: combining at least one reactive aluminosilicate, at least one solution of a moderator in water, and at least one solution of an alkaline silicate activator, wherein the solution moderator in water is a solution obtained by dissolving a soluble metal salt in water, wherein the soluble metal salt hydrolyzes in an alkaline solution and coprecipitates the silicate components present in the alkaline silicate activator solution, wherein said at least one solution of the moderator is combined with the with at least one alkaline silicate activator solution prior to mixing with said at least one reactive aluminosilicate, wherein said at least one moderator is selected from the group: anhydrous barium chloride, barium chloride dihydrate, barium nitrate, barium nitrite, and barium metaborate monohydrate, wherein said at least one retarder is used in an amount in the range of 0.5 to 10% by weight, based on the weight of the binder.

Brief description of the drawings

The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate exemplary embodiments of the invention and, together with the general description of the invention above and the detailed description of the invention below, are used to explain the features of the invention.

In FIG. 1 illustrates the Raman spectra for a sodium silicate activator solution that contains 0% to 5% barium chloride monohydrate PLMWH, in accordance with one embodiment of the present disclosure.

In FIG. 2 illustrates Raman spectra for co-deposited silicate materials that contain 0.5%, 0.75%, 0.875%, and 1.0% of PRMS barium chloride monohydrate, in accordance with one embodiment of the present disclosure.

Detailed description of the invention

Definitions

When the definition of terms deviates from the commonly used meaning of the term, the Applicant will assume the use of the definitions provided below, unless there is a specific indication.

As it is to be understood, the above general description of the invention and the following detailed description of the invention are exemplary and explanatory only and are not restrictive with respect to the claimed essence of any subject matter. In this application, the use of the singular will include the plural, unless there is a specific statement to the contrary. As it should be noted, as used in the specification and in the appended claims, the singular forms "one", "some" and "given" will include the plural equivalents, unless the context clearly dictates otherwise. In this application, the use of "or" will mean "and/or" unless otherwise stated. In addition, the use of the term "including", as well as other forms such as "include", "includes" and "included", is not limiting.

For the purposes of this disclosure, the term "comprising", the term "having", the term "comprising" and variations of these words are intended to be non-limiting and mean the possible presence of additional elements other than the listed elements.

For the purposes of this disclosure, location and direction terms such as "top", "bottom", "top", "bottom", "above", "below", "left", "right", "horizontal", " up, down, and the like are used merely for convenience in describing various embodiments of the present disclosure. Embodiments of the present disclosure may be oriented in various ways. For example, the diagrams, apparatus, and the like shown in the drawings may be rotated 180°, rotated 90° in any direction, reversed, and so on.

For the purposes of this disclosure, a value or property will be "based" on a particular value, property, condition, or other factor if that value is inferred by performing a mathematical calculation or logical decision using that value, property, or other factor.

As it should be noted for the purposes of this disclosure, in order to obtain a more concise description of the invention, some of the quantitative expressions presented in this document are not qualified by the term "approximately". It is to be understood that, whether the term "approximately" is used explicitly or not, each quantity presented herein is intended to mean an actual setpoint, and it also means an approximation to such a setpoint that would reasonably be expected based on the level of knowledge of a specialist in the relevant field of technology, including approximations due to the conditions of the experiment and/or measurement for such a given value.

For the purposes of this disclosure, the term "actual temperature" refers to the actual air temperature at any particular location as measured using a thermometer.

For the purposes of this disclosure, the term "WBCW" refers to the expression "by weight of binder", which is generally considered as the amount (in percent) of material added to cement when the material is added based on the total amount of a particular binder or mixture of binders. . In the case of geopolymer materials, the binders will typically be pozzolanic materials, referred to as pozzolanic precursor, which can be activated using alkaline solutions.

For the purposes of this disclosure, the term "cement" refers to a binder, which is a substance used for construction that sets, hardens, and adheres to other materials when bonding them together. Occasionally used on its own, cement can be used to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate results in masonry mortar, or cement mixed with sand and gravel results in concrete. The cements used in construction are usually inorganic, often based on lime or calcium silicate, and they can be characterized as either hydraulic or non-hydraulic, depending on the ability of the cement to hydrate in the presence of water.

For the purposes of this disclosure, the term "concrete" refers to a heavy, coarse-grained cementitious material made from a mixture of crushed stone or gravel, sand, cementitious material and water, which can be spread or poured into molds, and which forms a stone-like mass after hardening. Some embodiments may include a composite material formed from fine and coarse aggregate bonded together using a flowable cement (cement paste) that hardens over time. Most often Portland cement can be used, but other hydraulic cements such as calcium aluminate cement can sometimes be used. Geopolymers are considered as a new type of cementing materials that do not require the use of Portland cement.

For the purposes of this disclosure, the term "geopolymer" refers to environmentally friendly cementitious binder systems that do not require the use of Portland cement. In one narrow sense of the term, the geopolymers of the disclosed invention refer to inorganic polymers having a three-dimensional network structure similar to those of organic thermoset polymers. The matrix of the main chain of the disclosed geopolymers is an X-ray amorphous analogue of the zeolite framework, characterized by the presence of tetrahedral coordination of Si and Al atoms linked by oxygen bridges, while alkali metal cations (usually Na ⁺ and/or K ⁺ ) are associated with the material as charge compensators for AlO ₄ ^- . The geopolymers of the disclosed invention can be considered more broadly as a class of alkali activated materials (AAMs) formed from alkali aluminosilicate and/or alkaline earth aluminosilicate phases as a result of a reaction between a solid powdered aluminosilicate (the term "pozzolanic precursor") and alkaline activator.

For the purposes of this disclosure, the term "geopolymer composition" refers to a mixture composition consisting of pozzolanic precursors and an alkaline activator in solid or liquid form. In addition, the geopolymer composition may also include fine and coarse aggregates, fibers and other additives, depending on the application.

For the purposes of this disclosure, the term "mortar" refers to a workable paste containing fine aggregate and used to bond structural elements such as stones, bricks, and concrete building blocks together, fill and seal irregular gaps between them, and sometimes add decorative coloring or ornaments on handmade walls. In its broadest sense, mortar includes pitch, asphalt, and plastic ceramic mass (marsh) or clay, such as that used between wet pressed bricks. The cement or geopolymer mortar becomes solid as it cures, resulting in a rigid structure.

For the purposes of this disclosure, the term "room temperature" refers to a temperature in the range from about 15°C (59°F) to 25°C (77°F).

For the purposes of this disclosure, the term "setting" refers to the transformation of a plastic paste into a non-plastic and rigid mass.

For the purposes of this disclosure, the terms "set time" or "set time" refer to the time elapsed between the time water (alkaline activator solution) is added to the cement (pozzolanic precursor) and the time the paste begins to lose its plasticity (initial setting). The final setting time is the time elapsed between the moment water (alkaline activator solution) is added to the cement (pozzolanic precursor) and the time when the paste completely loses its plasticity and reaches a strength (strength) sufficient to withstand some specific pressure.

For the purposes of this disclosure, the term "moderately soluble in water" refers to a substance having a solubility ranging from 0.1 g per 100 ml of water to 1 g per 100 ml of water. Unless otherwise indicated, the terms "moderately soluble" and "moderately soluble in water" will be used interchangeably in the description below to refer to substances that are sparingly soluble in water.

For the purposes of this disclosure, the term "water-insoluble" refers to a substance that has a solubility of less than 0.1 g per 100 ml of water.

Description of the invention

Despite the susceptibility of the invention to various modifications and alternative forms, its specific embodiments by way of example have been shown in the drawings and will be described in detail below. However, as it is to be understood, the invention is not intended to be limited to the specific forms disclosed, but rather the invention is to cover all modifications, equivalents and alternatives falling within the scope and spirit of the invention.

Geopolymers are a class of alkali-activated binders that have a three-dimensional network structure similar to those of organic thermoset polymers. The matrix of the main chain of geopolymers is an X-ray amorphous analog of the framework of zeolites, characterized by the presence of tetrahedral coordination of Si and Al atoms connected by oxygen bridges, while alkali metal cations (usually Na ⁺ and/or K ⁺ ) are associated with the material as charge compensators for AlO ₄ ^- . The nominally empirical formula of geopolymers can be represented as M _n [–(SiO ₂ ) _z –AlO ₂ ] _n · wH ₂ O, where M is an alkaline cation; z is the molar ratio between Si and Al (1, 2 or 3); and n is the degree of polycondensation. Dissolution of a source of reactive aluminosilicate having a low Ca content by alkaline hydrolysis results in water consumption and the production of aluminate and silicate derivatives. This first step of geopolymerization is controlled by the ability of the alkaline compound to dissolve the fly ash based glass grid and produce small reactive components of silicates and aluminates:

Immediately after dissolution, these components become part of the aqueous phase, that is, the activating solution, which already contains silicate. Thus, a complex mixture of silicate, aluminate and aluminosilicate components is formed. The solution becomes more and more concentrated resulting in the formation of an alkali aluminosilicate gel (AAS) as these components in the aqueous phase form large networks through polycondensation:

After gelation, the system continues to reconfigure and reorganize as the cohesiveness of the gel network increases, resulting in a three-dimensional aluminosilicate network that sets and solidifies during the subsequent curing process.

Examples of these low-Ca reactive aluminosilicates include metakaolin (MK), certain calcined zeolites, and low-Ca class F fly ash (Low-Ca FFA).

Metakaolin is an amorphous aluminosilicate pozzolanic material and its use dates back to 1962 when it was incorporated into concrete for a dam at Jupia in Brazil. It is a thermally activated aluminosilicate material characterized by high pozzolanic activity, comparable to that of pyrogenic silica or exceeding it. It is formed by calcining kaolinite clay at a temperature ranging from 650° C. to 800° C., depending on the purity and degree of crystallinity of the precursor clays. Alkaline activation of the metakaolin results in a typical AAS material gel composition that will set and solidify at ambient temperatures. The mechanical properties and microstructure of the geopolymer are highly dependent on the initial Si/Al molar ratio. The best strength properties have been reported for blends having SiO ₂ /Al ₂ O ₃ ratios ranging from 3.0 to 3.8 with an M ₂ O/Al ₂ O ₃ molar ratio of approximately one.

Fly ash is a fine powdery substance that "flies up" from the coal combustion chamber (boiler) and is captured using emission control systems such as electrostatic precipitator or fabric "bag" dust collector and scrubbers. Approximately 131 million tons of fly ash is produced annually and approximately 56 million tons of this fly ash is recycled. Globally, approximately 65% of the fly ash produced is disposed of in landfills or ash and slag dumps. The combustion of anthracite and bituminous coal typically results in the production of class F fly ash, which contains less than 8% CaO. Fly ash is mainly formed from glassy spherical particles. The American Society for Testing and Materials (ASTM) C618 recognizes the existence of two main fly ash classes, class C and class F. The lower limit for (SiO ₂ + Al ₂ O ₃ + Fe ₂ O ₃ ) is class F fly ash ( FFA) is 70% and the corresponding value for Class C fly ash (CFA) is 50%. A high level of calcium oxide forms class C fly ash, which has cementing properties, resulting in the formation of calcium silicate and calcium aluminate hydrates when mixed with water without the need for alkaline activation. US Pat. No. 5,435,843 discloses a Class C alkali activated fly ash composition wherein the cement has an initial setting time of less than about 5 minutes. In general, Class F fly ash has a maximum calcium oxide level of approximately 18 wt %, while Class C fly ash generally has higher levels of calcium oxide, such as values ranging from 20 to 40% (mass.). The Low-Ca FFA material typically contains less than 8 wt % CaO. Geopolymers based on Low-Ca FFA material typically set and cure very slowly and have low final strength for curing at ambient temperatures (eg room temperature), but their reactivity increases as the cure temperature increases. The alkaline activation of Low-Ca FFA requires the use of a high curing temperature in order to make suitable building products for use. Alternatively, a more reactive aluminosilicate material, such as ground granular blast furnace slag (BFS) or metakaolin, must be mixed in to make geopolymer products that set and harden at ambient temperatures.

Crushed granular blast-furnace slag is another type of reactive aluminosilicate material that is enriched in alkaline earth oxides such as CaO and MgO. It is a glassy granular material that ranges from a coarse coarse porous loose structure having a diameter greater than 4.75 mm to dense grains the size of sand. Grinding leads to a reduction in particle size to the fineness of grinding cement, which makes it possible to use the material as an additional cementitious material in concrete based on Portland cement. Blast furnace slag is essentially calcium aluminosilicate glass, usually containing 27 - 38% SiO ₂ , 7 - 12% Al ₂ O ₃ , 34 - 43% CaO, 7 - 15% MgO, 0.2 - 1.6% Fe ₂ O ₃ , 0.15 - 0.76% MnO and 1.0 - 1.9% sulfur (mainly in the form of calcium sulfide) by weight. Blast-furnace slag is usually dispersed into fractions, dividing it into three grades, i.e., 80, 100 and 120, according to ASTM C989-92. In addition, ultrafine blast furnace slag is even more reactive than BFS 120 material. , and a specific surface area of approximately 800 m ² /kg. Since the BFS material is almost 100% glassy, it is generally more reactive than most fly ash. Alkaline activation of the BFS material results in essentially calcium silicate hydrate (CSH) and calcium aluminosilicate (CASH) gels. As is well known, geopolymers produced by alkaline activation of BFS material typically set and harden very quickly even at ambient temperature, resulting in a much higher ultimate strength than geopolymers produced using low content Class F fly ash. Some compositions have an initial setting time of less than 60 minutes, making mixing, laying and finishing difficult. It has been found that alkali activated slag has certain superior properties over Portland cement concrete, such as low heat of hydration, high early strength, and excellent durability in harsh environments. ¹ Based on a review of the published literature, this binder system has some serious problems, such as fast setting and high dry shrinkage. ^{2, 3} These issues must be resolved before the material can be used commercially.

Recently, the use of lignite and sub-bituminous coals has increased significantly, and a significant percentage of coal retains US fly ash production, which contains significant amounts of CaO. Fly ash characterized by high levels of CaO (High-Ca FFA), for example, in the range from more than 8% (wt.) to less than 20% (wt.), can still be classified by type. F in accordance with ASTM C-618. The setting times of fly ash based geopolymers decrease exponentially as CaO levels increase, and however, as CaO levels increase, compressive strength increases. ⁴ As established in the disclosed embodiments, freshly made geopolymers made using High-Ca FFA material containing 12.2 wt % CaO can experience flash setting. Geopolymers made using a CFA material containing more than 20% CaO typically set within 36 minutes, and instant setting, for example within a few minutes, is very common. ⁵ As it clearly follows, proper setting control is required in the manufacture of suitable building products for geopolymers made using High-Ca FFA (eg, greater than 8% CaO) and CFA materials. ⁶ Alkaline activation for High-Ca FFA material results in hydrated products such as CSH and CASH together with alkali aluminosilicate gel. The setting times of geopolymers also depend on the characteristics of the alkali activator solution, such as the molar concentration of alkali, the molar ratio of SiO ₂ /M ₂ O (M = Na, K) and between water and binder (water / binder). For example, the setting time decreases as the molar concentration of alkali metal hydroxide and the molar ratio of SiO ₂ /M ₂ O (M = Na, K) increase, but increase as the water / knit value increases. Conversely, the compressive strength of the hardened geopolymer increases with increasing alkali metal hydroxide molar concentration and SiO ₂ /M ₂ O (M = Na, K) molar ratio.

Class C fly ash exhibits a certain degree of similarity to blast furnace slag. Both materials are calcium aluminosilicate glasses. These pozzolanic materials are referred to as "reactive alkaline earth aluminosilicates" or "high Ca reactive aluminosilicates". In addition to BFS and CFA, High-Ca FFA, Vitreous Calcium Silicate (VCAS) and Clinker Kiln Dust (CKD) fall into this category. VCAS material is a waste product in the production of fiberglass. In one representative glass fiber manufacturing facility, typically approximately 10 to 20% (w/w) of the recycled glass material is not converted into a final product and is discarded as a by-product or VCAS waste and sent to a landfill for disposal. The VCAS material is 100% amorphous and its composition is very well matched, generally comprising approximately 50 - 55% (wt.) SiO ₂ , 15 - 20% (wt.) Al ₂ O ₃ and 20 - 25% (wt.) .) CaO. Crushed VCAS material exhibits pozzolanic activity comparable to that of silica dust and metakaolin when tested according to ASTM C618 and C1240. CKD material is a by-product in the manufacture of Portland cement and is industrial waste. Worldwide, more than 30 million tons of CKD material is produced annually, with significant amounts sent to landfills. A typical CKD material contains approximately 38 - 64% (wt.) CaO, 9 - 16% (wt.) SiO ₂ , 2.6 - 6.0% (wt.) Al ₂ O ₃ , 1.0 - 4.0 % (mass.) Fe ₂ O ₃ , 0.0 - 3.2% (mass.) MgO, 2.4 - 13% (mass.) K ₂ O, 0.0 - 2.0% (mass.) Na ₂ O, 1.6 - 18% (wt.) SO ₃ , 0.0 - 5.3% (wt.) Cl ^- and is characterized by a PPP value in the range of 5.0 - 25% (wt.). The CKD material is generally a very fine powder (eg, with a specific surface area in the range of approximately 4600 - 14000 cm ² /g). During alkaline activation, additional gelling of the CSH material, ettringite (3CaO ⋅ Al ₂ O ₃ ⋅ 3CaSO ₄ ⋅ 32H ₂ O) and/or syngenite (mixed alkali metal-calcium sulfate) will occur.

In general, geopolymers resulting from alkaline activation of these high-Ca reactive aluminosilicates set and harden very rapidly due to the instantaneous formation of calcium silicate hydrate and calcium aluminosilicate hydrate gels. In engineering practice, geopolymers should have reasonably long setting times. This means that concrete or mortar produced using a pozzolanic binder must have a setting time long enough to allow transport and installation. However, if the setting time is too long, this becomes uneconomical. In accordance with the disclosed embodiments, for successful applications of geopolymer materials in the construction industry, proper control of setting time when using a retarder is key.

Setting time control can be achieved by properly formulating an activator solution for high Ca aluminosilicate geopolymers. For example, the great value of water / knit. and a low concentration of alkali silicate can result in a geopolymer paste having a sufficiently long setting time or workability. However, the performance of the cured product is usually significantly adversely affected, and much lower strength and higher dry shrinkage are expected. In recent years, a variety of additives have been used to retard set in alkali activated cements or geopolymers, although their retardation efficiencies vary widely. ³ US Pat. No. 5,366,547 discloses a method of using a phosphate additive to delay the setting time of blast furnace slag activated by the use of sodium hydroxide. Examples of the phosphate moderator include sodium metaphosphate, sodium polyphosphate, potassium metaphosphate, and potassium polyphosphate. The retarding effect for these phosphate additives can vary when using a sodium silicate solution to activate the BFS material or other types of high Ca aluminosilicates. Authors Kalina et al. ⁷ used Na ₃ PO ₄ to retard the setting of blast furnace slag activated using sodium silicate. Solid sodium phosphate was mixed with the BFS material and then mixed with the sodium silicate activator solution. The compressive strength was significantly adversely affected (reduced) when a high dosage of retarder was used to achieve a long setting time or workability. The authors of Chang ⁸ and Chang et al. ⁹ concluded that the use of phosphoric acid alone extended the setting time of the alkali activated slag after reaching the critical concentration, but reduced the early compressive strength. The Ca ²⁺ ions released during the dissolution of blast-furnace slag in the highly alkaline solution are estimated to bind to the phosphate anion from the moderator. The formation of dihydrogen phosphate and subsequently calcium hydrogen phosphate structures results in a lack of calcium ions in solution, which in turn prevents nucleation and growth for CSH and CASH materials. Thus, the initial setting time is prolonged.

The effectiveness of certain retarders commonly used for Portland cement varies in geopolymers. Most retarders effective in Portland cement may not work in highly alkaline geopolymer systems. According to the observations of Wu et al. ¹⁰ Potassium or sodium tartrate did not show any effect on the initial setting time of the alkali activated slag, but reduced the final setting time slightly. As established by Rathanasak et al. ¹¹ , sucrose and gypsum, which work well in Portland cement, did not prolong the setting time of High-Ca FFA activated with sodium silicate. The authors of Brought et al. ¹² investigated the retarding effect of NaCl on set times in slag systems activated using sodium silicate. The addition of NaCl significantly retarded both setting and strength development at high dosages, but at low dosages, ie, 4% or less (w/w) of the slag, NaCl acted as an accelerator. In yet another slag system activated using sodium silicate ¹³ , a small effect of NaCl on the setting time was observed up to 20% addition based on the weight of the binder (WBMW), and setting was slowed beyond this point. However, the addition of such large amounts of chloride to reinforced geopolymer concrete can greatly accelerate the corrosion of the rebar profile and thus reduce service life.

Also very well known is the use of borates as retarders for Portland cement. However, as reported by Nicholson et al. ¹⁴ Borates added to alkali activated fly ash (class C) had no effect on setting behavior; on the contrary, a large amount of borates had a negative effect on the strength of binders. US Pat. No. 4,997,484 discloses a geopolymer composition based on an alkali metal hydroxide activated Class C fly ash (no soluble silicate content). Geopolymer compositions exhibit rapid strength development, for example, in the range of 1800 to 4000 ^psi (12.4 to 27.6 MPa) after curing at 73°F (22.8°C) for 3 to 4 hours despite for use as a borax retarder. The boron retarder was not effective in retarding the setting of the geopolymer based on the alkali activated CFA material. Both US Pat. No. 7,794,537 and US Pat. No. 7,846,250 disclose certain chemical compounds as retarders that are well known for Portland cement and geopolymer. Geopolymer compositions are based on either MK or FFA materials for oilfield applications or carbon dioxide storage. These compounds that retard the thickening of the cement slurry at elevated temperatures, eg 85°C, include borax (Na ₂ B ₄ O ₇ ⋅ 10H ₂ O), boric acid, sodium phosphoric acid, and lignosulfonate.

US Patent Application No. US 2011/0284223 discloses compositions and methods for well cementing applications that use organic compounds to retard thickening of geopolymer systems at elevated temperatures. Geopolymer compositions are not new and have been disclosed in the prior art and extensively researched in the literature. Preferred retarder compounds include the aminated polymer, aminophosphonates, quaternary ammonium compounds, and tertiary amines. However, despite the lack of uniqueness in the geopolymer composition itself, the effect of these retarders on hardened properties, such as compressive strength, has not been previously developed/reported.

Chinese patent CN 102249594B discloses complex retarders designed to delay the setting time of alkali activated blast-furnace slag. The complex retarder is formed from sodium chromate, a heterocyclic amino acid and a silicone surfactant. Chinese patent CN 1118438C discloses a complex moderator consisting of potassium chromate, sugar and phenol for sodium silicate activated slag. The initial setting can be adjusted in time period between 1 hour and 70 hours. However, this moderator may not be desirable because chromate is a highly mobile, easily migrating toxic anionic component and poses a risk of environmental pollution. Chinese Patent Application CN 101723607A discloses soluble zinc salts for delaying the setting time of blast furnace slag activated using sodium silicate. These zinc salts include nitrate, sulfate and chloride. Chinese patent applications CN 1699251A and CN 100340517C disclose barium salt as a moderator for alkali activated carbonite/blast furnace slag. Either the zinc or barium salt is dissolved in water and added to the blast furnace slag. After that, an alkaline activator solution is added to the mixture. Alternatively, powdered salt is ground together with blast furnace slag. After that, the activator solution is mixed into the solid mixture.

Unfortunately, most prior art moderators have only been developed for alkali activated slag. As is well known, the effectiveness of retarders is highly dependent on binder formulations. A retarder that is effective in Portland cement and alkali activated slag does not necessarily work well in geopolymer systems, such as systems made from High-Ca FFA, CFA materials, or a mixture of Low-Ca FFA and BFS materials.

In the methods disclosed in the prior art, there are mainly two significant mechanisms for slowing the setting times of the alkali activated slag. Retarders are added to chelate and/or precipitate the released Ca ²⁺ ion in order to prevent Ca ²⁺ from reacting with the silicate components already present in the alkali activator solution. In another method, retarders are added to form directly bonded protective layers on the surfaces of the anhydrous blast-furnace slag particles and thereby reduce their ability to dissolve in the highly alkaline solution. These adhering layers could be either adsorbed derivatives or insoluble calcium salts that precipitate and adhere to surfaces. In this case, this method is denoted by the term "protective layer". Chinese Patent CN 102249594B discloses the adsorption of a silicone surfactant on the surfaces of blast-furnace slag particles, the introduction of charge imparting components, which results in repulsion while reducing the Ca ²⁺ migration rate and/or reducing the electrostatic attraction of silicate anions, thereby , prevents gelation for CSH material. Ca ²⁺ cations released during the dissolution of blast furnace slag in a highly alkaline environment bind to phosphate anions from a phosphate moderator, eg Na ₃ PO ₄ . The formation of insoluble calcium phosphate compounds reduces the availability of Ca ²⁺ and thus stimulates the nucleation and growth of the poisoned CSH phase, and thus the setting time is extended. ⁷ Boron compounds dissolved in an alkaline solution form tetrahydroxyl borate, which, in turn, reacts with Ca ²⁺ . Precipitated calcium borate (eg Ca(B[OH] ₄ ) ₂ H ₂ O) partially or completely covers the surface of the blast-furnace slag particles. Thus, the presence of such impermeable layers of calcium borate prevents further dissolution of the blast furnace slag particles in the alkaline solution. ¹⁵ Soluble zinc salts are converted to a calcium zincate phase (eg CaZn ₂ (OH)6 ⋅ H ₂ O) which partially or completely coats the blast-furnace slag grains and thus passivates them for further hydration or alkaline activation. ^{16, 17} US Patent Application No. US 20160060170 discloses geopolymer compositions containing a nanoparticle retarder to control setting time. Reactive aluminosilicates include metakaolin, fly ash or rice husk ash. Prior to mixing with the sodium silicate activator solution, the reactive aluminosilicate particles are coated with nanoparticles such as halloysite nanotube particles or kaolin nanoclays. The nanoparticle coating is designed to slow down the geopolymerization reaction. Powdered blast-furnace slag/carbonatite is pre-mixed with a solution of barium salt. Due to the acquisition of a negative charge by the surfaces of blast-furnace slag particles in water, Ba ²⁺ cations will tend to be adsorbed on the surfaces of slag grains. After exposure to the alkali silicate solution, the insoluble barium deposits form a thin film on the slag grains and thus prevent the slag from coming into contact with the alkali solution (Chinese patent application CN 1699251A).

In the case of using the formation of protective layers on the surfaces of the pozzolanic particles to delay the setting time of alkali activated materials, a solution of metal salts such as barium nitrate must be mixed with the pozzolanic particles before mixing with the alkaline silicate solution to improve the degree of coverage of the protective coating.

In the disclosed embodiments, a novel process is provided using metal salts to delay the setting time of alkali activated materials or geopolymers. The fast setting of alkali activated reactive aluminosilicates having a high level of Ca content refers to the formation of gels of CSH and/or CASH materials at an early cure time. During the dissolution of the reactive aluminosilicate particles having a high Ca content, Ca ²⁺ cations are released and the cations almost instantly react with the silicate anions present in the alkaline solution. Setting control can be achieved using prior art methods, for example by removing Ca ²⁺ ions in an alkaline solution and/or by forming protective layers on the surfaces of the pozzolanic particles. Achievements of setting control can also be achieved by controlling the availability of silicate components for nucleation and gel growth of CSH and/or CASH materials. For example, in the disclosed method for well cementing geopolymers ¹⁸ powdered alkali silicate glass is used. Geopolymer paste at early curing time contains a small amount of silicate components. The powdered alkali silicate glass dissolves and releases the silicate components at a controlled rate during the early curing time, and thus the thickening and setting times are extended. However, this method results in hardened geopolymers which are not suitable for building materials applications where strengths greater than 30 MPa are required. Alternatively, the metal salts (eg, barium chloride) are dissolved in water, and then the resulting solution is mixed with the alkali silicate solution before mixing with the dry ingredients in a mixer. These metal salts, such as barium chloride, are hydrolysed in an alkaline solution, and silicate anions are co-precipitated during hydrolysis, leaving the activator solution depleted in silicate components. The degree of metal-silicate interactions depends on the metal/Si molar ratio, which determines the deceleration efficiency. The co-precipitated silicate slowly redissolves and becomes available for geopolymerization and/or gelling of the CSH and/or CASH materials during the subsequent curing process. Thus, the setting time is extended.

The disclosed method uses far fewer barium salts to achieve comparable setting times to those experienced with the "protective layer" method disclosed in Chinese Patent Applications CN 101723607A, CN 1699251A and CN 100340517C, where the metal salt solution must be premixed with solid matter, i.e. blast-furnace slag, to achieve a protective coating on the pozzolanic grains. For example, at least 2% ZNMP zinc salts have a retardation effect in blast furnace slag activated using sodium silicate. At least 4% of the barium salts of PRMS have a retarding effect in blast furnace slag/carbonatite activated using sodium silicate. In order to achieve a better degree of coverage with protective layers, a higher dosage of retarders is required, which, however, usually stimulates a significant decrease in the compressive strength of the cured product. In addition to this, the degree of coverage with protective layers is highly dependent on the surface charge of the pozzolanic particles. Despite the possibility that blast-furnace slag has a negative surface charge, the surface charge of fly ash can also be positive in solution. Therefore, when using the "guard layer" method, the effectiveness for the retardation effect can vary greatly between different sources of reactive aluminosilicates.

Thus, the disclosed embodiments provide effective inorganic retardants for controlling the thickening and setting times of a geopolymer composition that can be used as a well cement slurry, mortar and concrete.

In other embodiments described herein, geopolymer compositions are provided whose setting times may vary when an inorganic retarder is used. The geopolymer composition contains: (i) at least one class F low Ca fly ash containing calcium oxide in an amount less than or equal to 8 wt. %; (ii) at least one high-Ca aluminosilicate selected from the group consisting of blast furnace slag, class C fly ash, vitreous calcium silicate, and furnace dust; (iii) retarding solution; and (iv) an aqueous alkaline silicate activator.

The disclosed retarder solution is obtained by dissolving at least one soluble metal salt in water, where at least one soluble metal salt is selected from barium chloride, barium chloride dihydrate, barium nitrate, barium nitrite, barium metaborate monohydrate, nitrate hydrate barium, zinc nitrate, zinc chloride, zinc sulfate, lead chloride, lead nitrate, strontium chloride, strontium nitrate and strontium sulfate. Barium chloride and barium nitrate are preferred.

In one embodiment, at least one metal salt is dissolved in the retarder solution, and the retarder solution contains from about 0.1 to about 10% of the metal salts of PLMN. In one embodiment, the metal salt is barium chloride dihydrate. The dosage of barium chloride dihydrate is in the range of from about 0.10% to about 5% NLMW, and more preferably from about 0.5% to about 2.5% NLMW.

In one embodiment, the soluble barium salt is dissolved in water. Before mixing the activator solution with all other ingredients, the retarder solution is mixed with the alkali silicate activator solution. In yet another embodiment, the retarder solution and the activator solution are added separately while mixing with the other ingredients. The alkali silicate activator solution may contain metal hydroxides and metal silicates, where the metal is potassium, sodium, or combinations of both.

In the disclosed embodiment, a geopolymer composition is provided comprising: (i) at least one high-Ca aluminosilicate selected from the group consisting of BFS, CFA, vitreous calcium silicate, and kiln dust; (ii) moderator solution; and (iii) an alkaline silicate solution.

In one disclosed embodiment, the geopolymer composition comprises: (i) at least one high-Ca aluminosilicate selected from the group consisting of BFS, CFA, vitreous calcium silicate, and kiln dust; (ii) metakaolin; (iii) moderator solution; and (iv) an alkaline silicate solution.

In one disclosed embodiment, the geopolymer composition further comprises fine and/or coarse aggregates, superplasticizer or fiber for the purpose of making mortar and concrete for building applications.

In one disclosed embodiment, high quality and ultra high quality concrete compositions are provided whose setting times can be adjusted using an inorganic retarder. Compositions of high quality and ultra high quality concrete contain: (i) blast furnace slag; (ii) metakaolin; (iii) retarding solution; and (iv) an aqueous alkaline silicate activator; (v) at least a filler; and (vi) at least one micron/submicron filler.

One object of the present disclosure is to provide an effective retarding agent for controlling set times in a geopolymer composition that can be used as well cement slurry, mortar and concrete. In particular, the present disclosure provides an effective retardation method for controlling set in geopolymer systems containing High-Ca FFA material or high Ca aluminosilicate.

Low-Ca fly ash geopolymers

Geopolymers based on Low-Ca FFA material will set and cure very slowly and exhibit low ultimate strength when cured at low temperatures (eg room temperature) due to low fly ash reactivity in alkaline solution. The term "reactivity" is defined herein in relation to the relative weight of the pozzolan binder that reacts with the alkaline solution. Generally, fly ash having smaller particle sizes, such as ultrafine fly ash (UFFA), having an average particle size in the range of about 1 to 10 µm, is generally more reactive. The UFFA material is subjected to thorough processing as a result of the mechanical separation of the ultrafine fraction from the original fly ash. UFFA material can also lead to a decrease in the ratio of water./knit. to achieve the desired workability, such as slump, and results in a hardened geopolymer with better performance. Coal gasification power plants discharge coal gasification fly ash, typically in the form of SiO ₂ enriched, substantially spherical particles having a maximum particle size in the range of about 5 to 10 microns. Using less reactive fly ash to produce settable geopolymer products at ambient temperatures requires a second binder that is much more reactive.

Alkaline activation of metakaolin results in a typical geopolymer gel that has a reasonably long setting time, for example in the range of 2 to 6 hours. By admixing kaolin, the resulting geopolymer composition may not require the use of a retarder. In contrast, alkaline activation of BFS, CFA, CKD or VCAS materials results in substantially gels of CSH and/or CASH materials. The rapid settling of CSH and/or CASH materials shortens setting times and increases the rate of strength development as well as the final strength of the product. In the case of the second binder, which is a high Ca aluminosilicate pozzolan, the setting behavior of the resulting geopolymer system will be significantly modified. The setting times of a fly ash geopolymer generally decrease exponentially as the amount of mixed high Ca aluminosilicate pozzolans such as BFS material increases, in particular when using an alkali activator solution having a high molar concentration of alkali metal hydroxide and a high molar ratio of SiO ₂ /M ₂ O (M = Na, K), for the manufacture of geopolymer products suitable for use. Thus, for practical applications, proper setting control becomes necessary.

In one embodiment, the Low-Ca FFA material may be a fly ash that contains calcium oxide in an amount less than or equal to about 8% by weight. The fly ash classification is based on the ASTM C618 document, which should generally be understood by the state of the art. In one embodiment, the Low-Ca FFA material contains calcium oxide in an amount less than or equal to about 5% (wt.). In one embodiment, the fly ash must contain at least 65% (wt.) of the amorphous aluminosilicate phase and has an average particle diameter of 60 microns or less, such as 50 microns or less, such as 45 microns and less, thus, as 30 microns and less. In one embodiment, the Low-Ca FFA material has a loss on ignition (LOI) value of less than or equal to 5%. In one embodiment, the Low-Ca FFA material is characterized by an FIR less than or equal to 1%.

In one embodiment described herein, geopolymer compositions are provided whose setting times can be adjusted using an inorganic retarder. The Low-Ca FFA geopolymer composition comprises: (i) at least one class F low Ca fly ash containing less than or equal to 8 wt % calcium oxide; (ii) at least one high-Ca aluminosilicate selected from the group consisting of blast furnace slag, class C fly ash, vitreous calcium silicate, and furnace dust; (iii) retarding solution; and (iv) an aqueous alkaline silicate activator. The moderator solution is obtained by dissolving a soluble metal salt in water, where the soluble metal salt is selected from barium chloride, barium chloride dehydrate, barium nitrate, barium nitrite, barium metaborate monohydrate, barium nitrate hydrate, zinc nitrate, zinc chloride, zinc sulfate, strontium chloride , strontium nitrate and strontium sulfate. Soluble barium salts are preferred.

In one embodiment, the Low-Ca FFA material-based geopolymer compositions further comprise metakaolin; in one embodiment, the geopolymer compositions further comprise fine and coarse aggregates for making concrete products.

Geopolymers based on aluminosilicate with high Ca content

Alkaline activation for high-Ca aluminosilicate pozzolans typically results in immediate gels of CSH and/or CASH materials when exposed to a highly alkaline solution, resulting in very short setting times. In the absence of proper setting time management, these geopolymer materials could not be used in the manufacture of suitable products for use. Examples of these high Ca aluminosilicates include High-Ca FFA, CFA, BFS, VCAS, bottom ash and clinker kiln dust (CKD).

In one embodiment, a high-Ca aluminosilicate geopolymer composition is provided, comprising: (i) at least one high-Ca aluminosilicate selected from the group consisting of High-Ca FFA, BFS, CFA, vitreous calcium silicate and furnace dust; (ii) moderator solution; and (iii) at least one alkaline silicate solution.

In one embodiment, the high Ca aluminosilicate is a High-Ca FFA material; in one embodiment, the high Ca aluminosilicate is a BFS material; and in yet another embodiment, the high Ca aluminosilicate is a CFA material.

In one embodiment, the high Ca aluminosilicate geopolymer composition further comprises at least one low Ca aluminosilicate pozzolan selected from the group consisting of: Low-Ca FFA material and metakaolin. In one embodiment, the high-Ca aluminosilicate geopolymer composition also includes fine and coarse aggregates for making concrete products. In one embodiment, the geopolymer compositions further comprise fine and/or coarse aggregates for making concrete products.

High-quality and ultra-high-quality concrete

US Pat. No. 9,090,508 discloses geopolymer compositions for high performance and ultra high performance concrete. To achieve high and ultra-high quality geopolymer products, very reactive aluminosilicate materials, such as metakaolin and blast-furnace slag, must be used as a binder; the ratio of water./knit. should be small, for example, close to the minimum; the particulate packing density should be high to minimize product porosity, and coarse aggregates larger than 10 mm should not be used to favor homogeneity. Therefore, the setting times of freshly prepared concretes are relatively short, in particular when a large amount of blast-furnace slag is used in the formulations. The compositions disclosed in US Pat. No. 9,090,508 are essentially binary geopolymers based on blast-furnace slag/metakaolin.

In one embodiment described herein, high quality and ultra high quality concrete compositions are provided whose setting times can be adjusted using an inorganic retarder. High quality and ultra high quality concrete compositions contain: (i) blast furnace slag; (ii) metakaolin; (iii) retarding solution; and (iv) an aqueous alkaline silicate activator; (v) at least one filler; and (vi) at least one micron/submicron filler.

Ways to place the moderator

The retarder solution is obtained by dissolving at least one soluble metal salt in water, where at least one soluble metal salt is selected from barium chloride, barium chloride dehydrate, barium nitrate, barium nitrite, barium metaborate monohydrate, barium nitrate hydrate , zinc nitrate, zinc chloride, zinc sulfate, lead chloride, lead nitrate, strontium chloride, strontium nitrate and strontium sulfate. Any soluble metal salt that hydrolyzes in an alkaline solution and has the ability to co-precipitate the silicate components that are originally present in the alkaline silicate activator solution could be used as an inorganic retarding agent. The retarding effect depends on the type of metals as well as the dosage. As expected, metal-silicate interactions increase as the dosage or molar ratio between metal and silicate increases. Metal-silicate interactions should not be excessive. In the case of overwhelming interactions, the release of the silicate component into the geopolymer system will be greatly hampered during the subsequent curing process, and thus the early compressive strength of the product will be greatly adversely affected. Among all these metal salts, barium salts are preferred.

In one embodiment, at least one metal salt is dissolved in water. Before mixing all the ingredients, the retarder solution is mixed with the alkaline silicate activator solution. The alkali silicate activator solution combined with the retarder solution is poured into a mixer containing all dry ingredients. In yet another embodiment, the retarder solution and the activator solution are added separately during mixing with the dry ingredients to make the geopolymer product.

In one embodiment, prior to mixing with all other ingredients, the retarder solution is mixed with the alkali silicate activator solution for approximately 30 minutes. In yet another embodiment, the retarder solution is mixed with the alkali silicate activator solution for about 10 minutes before all ingredients are mixed. In yet another embodiment, the retarder solution is mixed with the alkali silicate activator solution for about 24 hours before all ingredients are mixed. In yet another embodiment, the retarder solution is added to the concrete during mixing in a ready mix truck. In this case, the retarder solution functions as an applied brake to prevent hardening of the mixing concrete in the ready-mix truck during transportation to the production site, for example, in an emergency situation.

In one embodiment, at least one metal salt is included in the retarder solution, and the retarder solution contains from about 0.1% to about 10% of the metal salts of PLMN. In one embodiment, the metal salt is barium chloride dihydrate. The dosage of barium chloride dihydrate is in the range of from about 0.10% to about 5% NLMW, and more preferably from about 0.5% to about 2.5% NLMW.

In one embodiment, the metal salt is barium metaborate monohydrate; in one embodiment, the moderator solution contains barium chloride dihydrate and zinc nitrate; in one embodiment, the moderator solution contains strontium nitrate and zinc chloride.

Deceleration mechanism

The following examples will illustrate the mechanism for delaying the setting time of the geopolymers of the present disclosure.

In accordance with the disclosed embodiments, the new method proposes the use of metal salts to control the setting time of alkali activated materials or geopolymers by controlling the release of silicate components in the activator solution, which are available to nucleate and grow gels of CSH and/or CASH materials at an early time. curing. In selected embodiments, experiments were conducted to study the technological process of silicate co-precipitation with hydrolyzed barium chloride in a solution of sodium silicate activator using Raman spectroscopy. In one series of tests, after mixing a solution of barium chloride dehydrate with a solution of sodium silicate for 0.5 hour, as the dosage of barium chloride was increased, Raman spectra were monitored for supernatant liquids and precipitates. In a second series of tests, combined barium chloride solutions and sodium silicate solutions were mixed and aged for 0.5, 2, and 24 hours, respectively, at a fixed dosage of barium chloride dihydrate. Thereafter, spectra of the supernatant liquid were recorded for these barium chloride/sodium silicate solutions.

Sodium hydroxide beads (99% pure) were dissolved in deionized water and combined with Type Ru sodium silicate solution from PQ Corp to form a sodium silicate activator solution. Separately, barium chloride dehydrate (99% purity) was dissolved in deionized water. Table 1 shows compositions of activator solutions. The NaOH molar concentration was fixed at 5 and the SiO ₂ /Na ₂ O mass ratio was 1.25 throughout Examples 1 to 4. The activator solution used for testing was part of a High-Ca FFA based geopolymer composition. , and the dosages of barium chloride dehydrate were expressed based on the weight of the binder based on fly ash.

Table 1

Example No. Sample ID Molar concentration of NaOH Mass ratio of SiO ₂ /Na ₂ O Moderator, PRNMP Molar ratio Ba/Si No. 1 RM-BC00 5.0 1.25 0.0% 0.00 No. 2 RM-BC0.875 5.0 1.25 0.875% 0.04 No. 3 RM-BC2.5 5.0 1.25 2.5% 0.12 No. 4 RM-BC5.0 5.0 1.25 5.0% 0.23

Raman spectra were accumulated using a Raman spectrograph microsystem with one diffraction grating—notch filter. The Melles–Griot Model 45 Ar ⁺ laser provided an incident light beam with a wavelength of 5145 Å, which was directed through a broadband polarization plane rotater (Newport Model PR-550) to a laser microscope, which displayed a beam of laser light on the precipitated solids or solution in 25 ml transparent cuvette through the objective of a Mitutoyo 10 microscope with a long focal length. The power of the laser light beam was approximately 22 mW on the sample. Scattered light was directed through the analyzer's polarizer, and the scattered light passed through a 150 µm aperture and then onto holographic notch and supernotch filters (Kaiser Optical Systems). The spectrograph used a diffraction grating at 1200 lines/mm (Richardson Grating Laboratory). The entrance slits of the JY-Horiba HR460 spectrograph were set to a resolution of 6 cm ^–1 to obtain spectra in the range from 50 to 1600 cm ^–1 . The spectrograph was frequency calibrated using CCl4 so that the recorded frequencies would have an accuracy within ± 1 cm ^–1 . Spectra were obtained under parallel polarization (VV), where the incident laser light beam was vertically polarized.

Table 2 lists the assignments of Raman oscillations. The assignments were made in accordance with the data of the authors Halasz et al. ^{19, 20} The results are presented in Figs. 1 for the supernatant solution and in FIG. 2 for precipitated solids.

table 2

Frequencies (cm ^{- 1} ) Attributions Relevant Components 1062 Assignment to the stretching vibration Si-O(x) Q ³ 1022 ν _as (x)O-Si-O(x) [x = H or -charge] ^Q2 924 _νs (H)O-Si-O(Na) ^Q1 834 _νs (Na)O-Si-O(Na) ^Q0 776 _δas (H)O-Si-O(H) ^Q0 606 _δas (Na)O-Si-O(Na) Ring with an axis of symmetry of the 3rd order 545 - Ring with an axis of symmetry of the 3rd order 447 δ _s (x)O-Si-O(x) [x = Na, H or -charge] Ring with an axis of symmetry of the 4th or 6th order

In FIG. 1 shows the Raman spectra for supernatant samples from sodium silicate solutions after mixing with a barium chloride solution for 0.5 hour at four doses of barium chloride dehydrate. As clearly demonstrated by the spectrum of the non-retardered activator solution (RM-BC-0), the activator solution is dominated by silicate components of the Q ⁰ , Q ¹ and Q ² types. The silicate component of type Q ⁰ is completely dissociated (FIG. 1). All supernatant solutions for samples containing barium chloride dihydrate (Table 1) are practically free of any silicate components, even at very low dosage at a Ba/Si molar ratio of 0.04 (RM-BC 0.875). This involves the coprecipitation of almost all of the silicate originally present in the activator solution together with the barium hydroxide by mixing the barium chloride solution with the alkaline sodium silicate activator solution. Due to precipitation of the silicate component as a barium silicate complex, the concentration of soluble silicate available for geopolymerization is very low during the early cure time. The limited availability of the silicate component prevents nucleation and gel growth of the CSH and/or CASH materials and thus results in a delayed set time.

In FIG. 2 shows Raman spectra for the coprecipitated solids after mixing with a barium chloride solution and an activator solution for 0.5 hour at three doses of moderator. The co-deposited sample with the lowest moderator dosage (RM-BC 0.875) shows a Raman spectrum with sharp lines, where a new vibrational band occurs in the region of 1062 cm ^–1 in addition to the bands corresponding to the silicate components of the types Q ⁰ , Q ¹ and Q ² . The band at 1062 cm ^–1 can be assigned to the ^Q3 silicate component. As it was found in the disclosed embodiments, based on a comparison of this Raman spectrum with the corresponding spectrum for the activator solution containing no moderator (Fig. 1, RM-BC00), the addition of the moderator stimulated a decrease in the relative proportion of completely dissociated silicate components (Q ⁰ ) together with other types of silicate component. As is evident, the barium cations interact with the silicate components to a certain extent resulting from increased polymerization progression of the silicate components.

As the moderator dosage increases, the intensities of the corresponding Raman bands decrease. When the amount of moderator was increased to 5% VNMW or a B/Si molar ratio of 0.23 (Fig. 2), the corresponding Raman bands disappeared almost completely, indicating the induction of significant interactions between the barium and the silicate component in the deposited complex. Increased interactions at a higher dosage of barium chloride dihydrate can result in a significantly delayed release of the silicate component and thus greatly prolong set times while still providing a set geopolymer with reduced early strength.

Examples

The essence of the subject in the example

The following examples will illustrate the practice of the present disclosure in its preferred embodiments.

The following starting materials were used to prepare the samples in Examples 1 to 21. Used two fly ash. One was High-CaO FFA (12.5%) material from Jewett Power Station, Texas, US, marketed by Headwater Resources, (Jewett fly ash). This fly ash contains 12.2% (wt.) CaO and is characterized by a loss on ignition (LOI) value of 0.15%. Its sum of oxides Si + Al + Fe is 79.57% (wt.), which exceeds 75% (wt.), and this value was the minimum requirement for class F fly ash in accordance with ASTM C618. The second fly ash was Low-Ca FFA from the Neilsens Group, Australia. This FFA material was a product of dispersion into larger fly ash fractions. It was characterized by a PPP value of less than 0.15%. Its sum of oxides Si + Al + Fe is approximately 93% (wt.). Grade 120 milled granulated blast furnace slag (NewCem Slag cement) was obtained from Lafarge-Holcim's Sparrow Point plant in Baltimore, MD. The activity score was approximately 129 according to ASTM C989. The blast furnace slag contained approximately 38.5% CaO, 38.2% SiO ₂ , 10.3% Al ₂ O ₃ and 9.2% MgO at an average particle size of 13.8 µm and at 50% (v/v) of particles smaller than than 7 µm. The metakaolin (Kaorock) was from Thiele Kaolin Company, Sandersville, GA. The metakaolin had a particle size ranging between 0.5 and 50 µm with 50% (vol.) of particles smaller than 4 µm. Quartz dust, an industrial waste product from Fe-Si fusion, came from Norchem Inc. The quartz dust contained 2.42 wt % carbon. Quartz dust was used to obtain solutions of activators as a result of dissolving quartz dust in an alkali metal hydroxide solution or was added as a submicron reactive filler when obtaining samples of ultra-high quality concretes.

The coarse aggregate used was Bluestone #7 (AASHTO T-27). The dry aggregate was immersed in water for 24 hours to achieve a saturated surface dry (SDS) state, after which free water was manually removed from the surface of the aggregate using a dry cloth. River sands were used either in the NPS state or in the state after drying in an oven to constant weight. A Trident hygrometer probe (model T90) was used to determine the moisture content in the fine aggregate sample. Min U-SIL® milled silica flour from U.S. Silica was used to produce ultra-high quality concrete. The silica flour had a particle size ranging between 1 and 25 µm with a median diameter of approximately 5 µm.

Type Ru sodium silicate solution from PQ, Corp. was used to prepare the alkali silicate activator solution. The mass ratio of SiO ₂ /Na ₂ O was approximately 2.40. The solution, not subjected after receiving any treatment, contains approximately 13.9% (mass.) Na ₂ O, 33.2% (mass.) SiO ₂ and 52.9% (mass.) water. To obtain an alkaline activator solution, sodium hydroxide beads (99% purity) and potassium hydroxide flakes (91% purity) were used.

Examples 1 to 7

Received geopolymer samples containing high Ca fly ash class F from the company Jewett Power Station, Texas, USA. The blend compositions were shown in Table 3 and the ingredients were shown in grams. The batch size was approximately 5000 grams. The Jewett fly ash contained approximately 12.2 wt % CaO. For comparison, geopolymer samples from Examples Nos. 1 and 2 were prepared using sodium hexametaphosphate (SHMP) moderator. Sodium phosphate as a moderator has been disclosed in the prior art or in the literature. The dosage of the SHMP material was, respectively, 1.50% and 2.25% of the PLMWP. To demonstrate the retardation effectiveness, the geopolymer samples of Examples #4 to #7 were prepared using a sodium chloride dihydrate moderator at dosages ranging from 0.50% to 1.00% (w/w) of the CLMP.

NaOH beads (99% pure) were dissolved in water to prepare the activator solution, and then the resulting solution was combined with the Type Ru sodium silicate solution. To obtain a moderator solution, barium chloride dihydrate or sodium metaphosphate (SHMP) was dissolved separately in water. The retarder solution was mixed for 2 hours and then poured into the Jewett fly ash in a K-Lab high intensity mixer (Kercher Industries) for 6 minutes. The resulting freshly prepared pastes were immediately molded (3'' (76.2 mm) high and 40 mm high) followed by a shaking table treatment for approximately 1 minute to remove entrapped air bubbles. For freshly prepared pastes, initial and final setting times were determined using the Vicatronic Automatic Vicat instrument (Model E004N), hereinafter referred to as the AutoVicat device, in accordance with ASTM C191.

Table 3

Example No. Sample ID sodium silicate Sodium hydroxide Water fly ash Barium chloride dihydrate SHMP Setting time (minutes) Start End No. 1 MP1.50 579.0 98.3 672.9 3650.9 0 54.8 35 57 No. 2 MP2.25 579.0 98.3 672.9 3650.9 0 82.1 38 63 No. 3 BC0.00 579.0 98.3 672.9 3650.9 0 0 29 45 No. 4 BC0.50 579.0 98.3 672.9 3650.9 18.4 0 47 78 No. 5 BC0.75 579.0 98.3 672.9 3650.9 27.7 0 68 99 No. 6 BC0.875 579.0 98.3 672.9 3650.9 32.3 0 114 144 No. 7 BC1.00 579.0 98.3 672.9 3650.9 36.9 0 391 450

The initial setting time for the control sample (Example 3, BC00) was defined as 29 minutes and the final setting time was 45 minutes. With the addition of 0.50% PRNMW barium chloride dihydrate, the initial setting time was increased to 47 minutes, and the final setting time was increased to 78 minutes (example 4). With an increase in the amount of barium chloride dihydrate to 0.75% NLMWH, the initial setting time increased to 68 minutes, and the final setting time increased to 99 minutes (example 5). With an increase in the amount of barium chloride dihydrate to 0.875% NLMWH, the initial setting time increased to 114 minutes, and the final setting time increased to 144 minutes (example 6). With a further increase in the amount of barium chloride dihydrate to 1% NLMWH, the initial setting time increased to 391 minutes, and the final setting time to 450 minutes (example 7). As revealed by isothermal calorimetry data, the addition of a moderator leads to a significant decrease in the heat of hydration of geopolymers.

As established by comparison, when 1.5% NLMWH sodium metaphosphate was mixed in, the initial setting time was 35 minutes and the final setting time was 57 minutes. Increasing the amount of sodium metaphosphate to 2.25% NLMWP slightly increased the initial setting time to 38 minutes and the final setting time to 63 minutes. As is obvious, the present moderator is much more effective than the moderator disclosed in the prior art or in the literature.

Examples 8 to 10

The mix compositions shown in Table 4 were used to prepare samples of the two-component geopolymer mortar based on FFA/BFS materials. Ingredients are shown in grams. In a 7 quart (6.62 dm ³ ) Waring 7 planetary mixer, low-Ca Class F fly ash from Neilsens Concrete, Australia, ground granulated blast furnace slag from Lafarge-Holcim, and river sand (in saturated surface-dry state). NaOH beads were dissolved in water to prepare an activator solution, and then the resulting solution was combined with a Type Ru sodium silicate solution. The activator solution was left alone overnight before use. Separately, barium chloride dihydrate was dissolved in water, if used. The dosage of the retarder was fixed at 0.875% of the NLMWP.

The activator solution free of barium chloride dihydrate (Example No. 8) was poured into the FFA/BFS/sand mixture and mixed for 5 minutes at an intermediate speed. For fresh mortar, setting times were measured using an AutoVicat device in accordance with ASTM C191. The initial setting time was 114 minutes and the final setting time was 186 minutes.

Prior to obtaining a sample of geopolymer mortar (example 9), the retarder solution was mixed with the activator solution for 30 minutes. For fresh mortar, setting times were measured using an AutoVicat device in accordance with ASTM C191. The initial setting time was 249 minutes and the final setting time was 348 minutes.

The retarder solution was added while the activator solution was being poured into the dry mixture of ingredients (Example 10). The mixture was mixed for 5 minutes. For fresh mortar, setting times were measured using an AutoVicat device in accordance with ASTM C191. The initial setting time was 236 minutes and the final setting time was 342 minutes.

Table 4

No. example Sodium silicate Sodium hydroxide Water FFA bfs river sand Barium chloride dihydrate Setting time (min) Start End 8 252.3 49.23 268.2 714.1 178.5 1450.8 0 114 186 9 252.3 49.23 268.2 714.1 178.5 1450.8 7.59 236 342 10 252.3 49.23 268.2 714.1 178.5 1450.8 7.59 249 348

Examples 11 to 13

The same mixture composition as the mixture composition used in Examples 8 to 10 was used to prepare samples of a two-component geopolymer mortar based on FFA/BFS materials (Table 4). A 7 quart (6.62 dm ³ ) Waring 7 planetary mixer mixed low-Ca Class F fly ash from the Neilsens Group, Australia, ground granular blast furnace slag from Wagners, Australia, and river sand (in saturated surface-dry state). NaOH beads were dissolved in water to prepare an activator solution, and then the resulting solution was combined with a Type Ru sodium silicate solution. The activator solution was left alone overnight before use. Separately, barium chloride dihydrate was dissolved in water, if used. The dosage of the retarder was fixed at 1.25% of the VNMW.

The activator solution free of barium chloride dihydrate (Example No. 11) was poured into the FFA/BFS/sand mixture and mixed for 5 minutes at an intermediate speed. For fresh mortar, setting times were measured using an AutoVicat device in accordance with ASTM C191. The initial setting time was 59 minutes and the final setting time was 144 minutes. The compressive strength was 4081 psi ( ^28.1 MPa) after curing for 7 days and increased to 8032 ^psi (55.4 MPa) after curing for 28 days.

Prior to obtaining a sample of geopolymer mortar (example 12), the retarder solution was mixed with the activator solution for 30 minutes. For fresh mortar, setting times were measured using an AutoVicat device in accordance with ASTM C191. The initial setting time was 136 minutes and the final setting time was 198 minutes. The compressive strength was 3673 psi (25.3 ^MPa ) after curing for 7 days and increased to 7734 ^psi (53.3 MPa) after curing for 28 days.

The retarder solution was added while the activator solution was being poured into the dry mixture of ingredients (Example 13). The mixture was mixed for 5 minutes. For fresh mortar, setting times were measured using an AutoVicat device in accordance with ASTM C191. The initial setting time was 114 minutes and the final setting time was 180 minutes. The compressive strength was 4064 psi ( ^28.0 MPa) after curing for 7 days and increased to 7970 ^psi (55.0 MPa) after curing for 28 days.

Examples 14 to 16

Metakaolin (5.71 wt %) and crushed granulated blast furnace slag (14.72 wt %) were mixed in a high intensity mixer (K-Lab, Kercher Industries) to prepare geopolymer ultra high performance concrete (GUHPC). The activator was obtained by mixing Na ₂ O (2.12% (wt.)) in the form of NaOH, K ₂ O (1.35% (wt.)) in the form of KOH, SiO ₂ (3.95% (wt.) ) in the form of a solution of sodium silicate Type Ru and water (10.15% (wt.)). Prior to obtaining the samples, barium chloride dihydrate was dissolved separately in water, if used, and then combined with the activator solution for 5 minutes. Subsequently, the activator solution was poured into the MK/BFS materials mixture and mixed for 3 minutes at approximately 350 rpm. After that, dry river sand (50% (wt.)) and quartz flour (10.00% (wt.)) were added to the mixture and continued to be mixed for 3 minutes. Toward the end of mixing, quartz dust (2.00%) was added and mixing was continued for 3 minutes. The resulting paste was tested for initial setting time using an AutoVicat or using a manual Vicat. The resulting paste was poured into 2''×4'' (50.8 mm×101.6 mm) cylindrical molds and cured at room temperature. Compressive strength was measured after curing for 28 days using a Test Mark CM-4000-SD compression tester. The compression test machine was calibrated to NIST Traceable standards.

In the absence of barium chloride dihydrate (Example 14), the initial set time was estimated to be approximately 30 minutes and the compressive strength was approximately 19972 ^psi (137.7 MPa) after curing for 28 days. In the case of adding 1% (w/w) WLMP barium chloride dihydrate (Example 15), the initial setting time was 54 minutes and the compressive strength was approximately 20146 ^psi (138.9 MPa) after curing for 28 days. In the case of adding 2% (wt.) VNMP of barium chloride dihydrate (example 16), the initial setting time was increased to 89 minutes, and the compressive strength was approximately 19424 lb/in ² (133.9 MPa) after curing for 28 days.

Examples 17 to 18

In a high intensity mixer (K-Lab, Kercher Industries), metakaolin (5.92 wt. %) and pulverized granular blast-furnace slag (15.28 wt. %) were mixed in a high-intensity mixer (K-Lab, Kercher Industries) to obtain samples of the GUHPC material. The activator was obtained by mixing Na ₂ O (1.08% (wt.)) in the form of NaOH, K ₂ O (2.47% (wt.)) in the form of KOH, SiO ₂ (3.80% (wt.) ) in the form of quartz dust and water (9.45% (mass.)). The quartz dust was dissolved in an alkali metal hydroxide solution and the resulting activator solution was aged for a week prior to use. Prior to obtaining the samples, barium chloride dihydrate was dissolved separately in water, if used, and then combined with the activator solution for 10 minutes. Subsequently, the activator solution was poured into the MK/BFS materials mixture and mixed for 3 minutes at approximately 350 rpm. After that, dry river sand (50% (wt.)) and quartz flour (10.00% (wt.)) were added to the mixture and continued to be mixed for 3 minutes. Toward the end of mixing, quartz dust (2.00%) was added and mixing was continued for 3 minutes. The resulting paste was subjected to initial and final setting times using a hand-held Vicat device. The paste was poured into 2'' x 4'' (50.8 mm x 101.6 mm) cylindrical molds and cured at room temperature. The compressive strength was measured after curing for 28 days.

In the absence of barium chloride dihydrate (Example 17), the initial setting time was approximately 15 minutes, the final setting time was approximately 19 minutes, and the compressive strength was approximately 26418 ^psi (182.1 MPa) after curing for 28 days. In the case of adding 1.5% (wt.) WBCW barium chloride dihydrate (Example 18), the initial setting time was 73 minutes, the final setting time was 81 minutes, and the compressive strength was approximately 23817 ^psi (164.2 MPa ) after curing for 28 days.

Examples 19 to 20

Examples 19 and 20 demonstrate the effectiveness of setting control when using soluble barium salt in geopolymer concretes.

The mixture composition for both concrete samples contained 78.75% (wt.) aggregates with a mass ratio between coarse and fine aggregates of 1.74. The binder contained 80% Low-CaO FFA material and 20% blast furnace slag. The ratio of water./knit. was 0.47, the molar concentration of NaOH was 5.7, and the mass ratio of SiO ₂ /Na ₂ O was 1.15 for the activator solution. To obtain samples of geopolymer concrete in a high-intensity mixer (K-Lab, Kercher Industries), Low-CaO FFA from Neilsens Group, Australia, blast-furnace slag from Lafarge-Holcim and river sand (in the NPS condition) were mixed for 3 minutes. NaOH beads were dissolved in water to prepare an activator solution, and then the resulting solution was combined with a Type Ru sodium silicate solution. The activator solution was left alone overnight before use.

The retarder free activator solution (Example No. 19) was poured into the FFA/BFS/sand mixture and mixed for 3 minutes at 300 rpm. After that, coarse aggregate in the state of NPS (grade No. 7) was added and mixing was carried out for 5 minutes at a low mixing speed (for example, 20 rpm). The freshly prepared concrete was sieved to obtain a mortar sample, which was measured using an Acme Penetrometer to measure setting times in accordance with ASTM C403. The freshly prepared concrete was also poured into 3'' x 6'' (76.2 mm x 152.4 mm) cylindrical molds and vibrated for 1 minute on a vibrating table. The samples were restrained and cured at room temperature until the compressive strength was measured. The initial setting time was 75 minutes and the final setting time was 168 minutes. The compressive strength after curing for 7 days was 4509 ^psi (31.1 MPa) and increased to 7992 ^psi (55.1 MPa) after curing for 28 days.

Using the same procedure as the procedure described in Example 19, additional concrete samples containing the retarder were obtained (Example 20). Barium chloride dihydrate was dissolved separately in water. The dosage of the retarder was 1.00% of the NLMK. Before obtaining a sample of freshly prepared concrete, the retarder solution was mixed for 30 minutes with the activator solution. Freshly prepared concrete was screened to obtain a mortar sample for measuring setting times using an Acme Penetrometer in accordance with ASTM C403. The initial setting time was 313 minutes and the final setting time was 572 minutes. The compressive strength was 3707 ^psi (25.6 MPa) after curing for 7 days and 7259 ^psi (50.0 MPa) after curing for 28 days.

Example 21

The same mixture composition, not containing the retarder solution, as the mixture composition in example No. 8, was mixed for 30 minutes, and after that, the retarder solution (3% barium chloride PRMS) was poured into the paste while mixing, and additional mixing was carried out for 10 minutes. After cessation of mixing, the mortar sample was subjected to a setting time determination in accordance with ASTM C191. At about 7.4 hours after pouring the activator solution into the dry mix, the mortar sample did not show any sign of setting, indicating that the retarder was actually effective in delaying set. The retarder can be used as an emergency deployed brake for freshly prepared geopolymer concrete being transported in a ready mix truck.

After a detailed description of the many embodiments of the present disclosure of the invention should be obvious the possibility of the existence of modifications and variations that do not deviate from the scope of the invention defined in the accompanying claims. In addition, as it is to be understood, all examples in the present disclosure, while illustrating a variety of embodiments of the invention, are offered as non-limiting examples and should therefore not be taken as limiting the various aspects thus illustrated.

Literary references

The following references are referred to above in this document and are hereby incorporated by reference into this document:

1. D. M. Roy, G. M. Idor, "Hydration, Structure, and Properties of Blast Furnace Slag Cements, Mortars, and Concrete," ACI Materials Journal 79 (1982) pp. 444-457.

2. S. D. Wang, X. C. Pu, K. L. Scrivener, P. L. Pratt, "Alkali-activated Slag Cement and Concrete: A Review of Properties and Problems," Advance in Cement Research 27 (1995) pp. 93-102.

3. J. L. Provis, J. S. J. van Deventer, Alkali Activated Materials. Springer: Houten, The Netherlands, 2014.

4. E. I. Diaz, E. N. Allouche, S. Eklund, “Factors Affecting the Suitability of Fly Ash as Source Material for Geopolymers,” Fuel 89 (2010) pp. 992-999.

5. E. I. Diaz-Loya, E. N. Allouche, and S. Vaidya, "Mechanical Properties of Fly-Ash-Based Geopolymer Concrete," ACI Materials Journal 108 (2011) pp. 300-306.

6. P. Topark-Ngarm, P. Chindaprasirt, and V. Sata, "Setting Time, Strength, and Bond of High-Calcium Fly Ash Geopolymer Concrete," Journal of Materials in Civil Engineering 27 (2015).

7. L. Kalina, V. Bílek Jr., R. Novotný, M. Mončeková, J. Másilko and J. Koplík, “Effect of Na ₃ PO ₄ on the Hydration Process of Alkali-Activated Blast Furnace Slag,” Materials 9 (2016) pp. 395-403.

8. J. J. Chang, "A Study on the Setting Characteristics of Sodium Silicate-activated Slag Pastes," Cement and Concrete Research 33 (2003) pp. 1005-1011.

9. J. J. Chang, W. C. Yeih, C. C. Hung, "Effects of Gypsum and Phosphoric Acid on the Properties of Sodium Silicate-based Alkali-activated Slag Pastes," Cement and Concrete Composites 27 (2005) pp. 85-91.

10. C. Wu, Y. Zhang, Z. Hu, "Properties and Application of Alkali-slag Cement," Journal of the Chinese Ceramic Society 21 (1993) pp. 175-181.

11. U. Rattanasak, K. Pankhet, P. Chindaprasirt, "Effect of Chemical Admixtures on Properties of High-calcium Fly Ash Geopolymer," International Journal of Minerals Metallurgy and Materials 18 (2011) pp. 364-369.

12. A. R Brough, M. Holloway, J. Sykes, A. Atkinson, “Sodium silicate-based alkali-activated slag mortars: Part II. The retarding effect of additions of sodium chloride or malic acid,” Cement and Concrete Research 30 (2000) pp. 1375-1379.

13. A. R. Sakulich, E. Anderson, C. Schauer, M. W. Barsoum, “Mechanical and Microstructural Characterization of an Alkali-activated Slag/Limestone Fine Aggregate Concrete,” Construction and Building Materials 23 (2009) pp. 2951-2957.

14. C. L. Nicholson, B. J. Murray, R. A. Fletcher, D. Brew, K. J. Mackenzie, M. Schmücker, Novel Geopolymer Materials Containing Borate Structural Units. In Proceedings of the World Congress Geopolymer, Perth, Australia, September 2005; pp. 31-33.

15. M. Davraz, “The Effects of Boron Compounds on the Properties of Cementitious Composites,” Science and Engineering of Composite Materials 17 (2010) pp. 1-18.

16. G. R. Qian, D. D. Sun, J. H. Tay, “Characterization of mercury- and zinc-doped alkali-activated slag matrix Part II. Zinc," Cement and Concrete Research 33 (2003) pp. 1257-1262.

17. G. R. Qian, D. D. Sun, J. H. Tay, "Immobilization of Mercury and Zinc in an Alkali-activated Slag Matrix," Journal of Hazardous Materials B101 (2003) 65-77.

18. W. L. Gong, H. Xu, W. Lutze, I. L. Pegg, "Pumpable Geopolymer Compositions for Well Sealing Applications," US patent application 15/597,227, filed May 17, 2017, pending (2016).

19. I. Halasz, M. Agarwal, R. B. Li, N. Miller, "What Can Vibrational Spectroscopy Tell about the Structure of Dissolved Sodium Silicates?" Microporous and Mesoporous Materials 135 (2010) pp. 74-81.

20. I. Halasz, M. Agarwal, RB Li, N. Miller, "Vibrational Spectra and Dissociation of Aqueous Na ₂ SiO ₃ Solutions" Catalysis Letters 117 (2007) pp. 34-42.

All documents, patents, journal articles and other materials cited in this application are incorporated herein by reference.

Despite the description of the present disclosure of the invention when referring to certain embodiments, numerous modifications, changes and modifications of the described embodiments are possible without deviating from the scope and scope of the present disclosure, in accordance with the definition of the invention in the accompanying claims. Accordingly, the present disclosure is not intended to be limited by the described embodiments, but is intended to be within the full scope of the following claims and their equivalents.

Claims (37)

1. Geopolymer composition, characterized by a controlled setting time and containing: at least one reactive aluminosilicate; at least one solution of the moderator in water, and at least one alkaline silicate activator solution, wherein at least one moderator is a soluble metal salt that hydrolyzes in an alkaline solution and co-precipitates the silicate components present in the alkaline silicate activator solution, wherein said at least one retarder solution is combined with said at least one alkaline silicate activator solution prior to mixing with said at least one reactive aluminosilicate, wherein said at least one moderator is selected from the group: anhydrous barium chloride, barium chloride dihydrate, barium nitrate, barium nitrite and barium metaborate monohydrate, moreover, the specified at least one retarder is used in an amount in the range from 0.5 to 10 wt.% when calculating the weight of the binder. 2. A geopolymer composition according to claim 1, which contains at least two reactive aluminosilicates, class F low-Ca fly ash and blast-furnace slag. 3. The geopolymer composition of claim 2, wherein the class F low Ca fly ash is a fly ash that contains less than or equal to 8 wt% calcium oxide. 4. The geopolymer composition of claim 3, wherein the fly ash contains at least 65% by weight of an amorphous aluminosilicate phase. 5. The geopolymer composition of claim 3, wherein the fly ash has an average particle diameter selected from: 60 µm or less, 50 µm or less, 45 µm or less, and 30 µm or less. 6. The geopolymer composition of claim 2, wherein the class F low Ca fly ash has a loss on ignition value of less than or equal to 5%. 7. Geopolymer composition according to claim 2, which, in addition to the above reactive aluminosilicates, additionally contains reactive aluminosilicate metakaolin. 8. The geopolymer composition of claim 1, wherein the at least one reactive aluminosilicate is at least one high Ca aluminosilicate selected from the group: high Ca fly ash class F, fly ash class C, blast furnace slag , vitreous calcium silicate, ash and slag waste and kiln clinker dust. 9. The geopolymer composition of claim 8 wherein the one reactive aluminosilicate is metakaolin. 10. Geopolymer composition according to claim 1, which contains at least two reactive aluminosilicates - blast furnace slag and metakaolin. 11. Geopolymer composition according to claim 1, which contains at least two reactive aluminosilicates - class C fly ash and metakaolin. 12. The geopolymer composition of claim 1, wherein the alkaline silicate activator solution contains metal hydroxides and metal silicates, where the metal is potassium, sodium, or combinations of both. 13. Geopolymer composition according to claim 1, additionally containing at least one aggregate. 14. Geopolymer composition according to claim 1, additionally containing at least one micron or submicron filler. 15. Geopolymer composition according to claim 1, the initial setting time of which is in the range from 25 minutes to 24 hours. 16. Geopolymer composition according to claim 1, the initial setting time of which is in the range from 45 to 180 minutes. 17. Geopolymer composition according to claim 1, the initial setting time of which is in the range from 90 to 360 minutes. 18. A method for obtaining a geopolymer composition characterized by a controlled setting time, including: combining at least one reactive aluminosilicate, at least one solution of the moderator in water and at least one solution of an alkaline silicate activator, where the solution of the moderator in water is a solution obtained by dissolving a soluble metal salt in water, and the soluble metal salt hydrolyzes in an alkaline solution and co-precipitates the silicate components present in the alkaline silicate activator solution, wherein said at least one retarder solution is combined with said at least one alkaline silicate activator solution prior to mixing with said at least one reactive aluminosilicate, wherein said at least one moderator is selected from the group: anhydrous barium chloride, barium chloride dihydrate, barium nitrate, barium nitrite and barium metaborate monohydrate, moreover, the specified at least one retarder is used in an amount in the range from 0.5 to 10 wt.% when calculating the weight of the binder. 19. The method of claim 18, wherein the geopolymer composition contains at least two reactive aluminosilicates, low-Ca class F fly ash and blast-furnace slag. 20. The method of claim 19, wherein the class F low Ca fly ash is a fly ash that contains less than or equal to 8 wt% calcium oxide. 21. The method according to p. 19, in which the geopolymer composition, in addition to the above reactive aluminosilicates, additionally contains a reactive aluminosilicate metakaolin. 22. The method according to claim 18, in which the geopolymer composition, as at least one reactive aluminosilicate, contains at least one high-Ca aluminosilicate selected from the group: high-Ca content fly ash class F, fly ash class C , blast-furnace slag, vitreous calcium silicate, ash and slag waste and kiln clinker dust. 23. The method according to p. 22, in which the geopolymer composition contains metakaolin as one reactive aluminosilicate. 24. The method according to claim 18, in which the geopolymer composition contains at least two reactive aluminosilicates - blast furnace slag and metakaolin. 25. The method according to claim 18, in which the geopolymer composition contains at least two reactive aluminosilicates - class C fly ash and metakaolin. 26. The method of claim 18, wherein the water solution of the retarder is mixed with the alkaline silicate activator solution for one of 10 minutes, 30 minutes and 24 hours before mixing with all other ingredients.

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