TWM628911U - Spray system and repair and/or retrofitted building structure - Google Patents

Abstract

A spray system comprises a spray body having a chamber and a nozzle connected to the chamber, and a sprayable ductile metal-like cementitious composition (SDMCC) received in the chamber and adapted to be sprayed through the nozzle. The SDMCC comprises: a composite binder, fibres, and water; wherein the composite binder comprises a cement component and a pozzolan component. The SDMCC may exhibit expansion on curing and strain hardening behaviour. Also described is a repaired and/or retrofitted building structure comprising a building structure, and a repair layer which is made from the SDMCC comprised in the spray system, and which is disposed on a surface of the building structure.

Description

Spray systems and restored and/or refurbished building structures

creative field

This work is about sprayable ductile metal-like cementitious compositions (SDMCC). This work is also about the use of SDMCC for repairing or refurbishing building structures such as underground pipelines and how to use them.

creative background

Underground pipelines are critical infrastructure and can be used to transport and distribute water, including potable and wastewater, for various purposes. Pipelines used for these purposes are often subjected to heavy mechanical loads and environmental stresses. Therefore, both metal pipes and concrete pipes are prone to problems such as cracking, spalling, and accumulation of debris. Metal pipes may corrode or deform. If not repaired, these problems can lead to line failure.

Excavation-free pipeline repair techniques are techniques that can be used to repair existing pipelines with minimal damage. Reduced construction costs, reduced environmental impact, and reduced public disturbance mean that excavation-free pipeline repair techniques are often preferred over trenching methods. Known excavation-free pipeline repair methods include cured-in-place pipe (CIPP) methods, slip linings, close-fit pipe methods, helically wound lining methods, segment continuous linings, and sprayed linings. Sprayed linings with cement-based materials may offer advantages such as lower cost and faster construction compared to other methods. It can also form continuous jointless spray lining.

The sprayed lining method involves spraying a cementitious or polymer-based material onto the on the inner surface of existing pipelines. Cementitious materials are low cost but generally provide poor corrosion protection for steel mains. Polymer-based materials generally have better corrosion resistance, but are more expensive. Once sprayed onto the substrate, the material must have good adhesion and cohesion to build up to the desired thickness. The inner surface of the pipeline is generally not conducive to coating materials. Although pipelines are often cleaned prior to spraying, the lack of adhesion between the sprayed material and the inner pipe wall remains a major problem.

Conventional cementitious materials are brittle and do not have tensile resistance. In order to obtain high strength and dense microstructures, cementitious restorative materials typically contain large amounts of fine and reactive powders and require low water content. This combination makes the cementitious material highly shrinkable, which can cause limited shrinkage rupture. After the rupture, the fluid in the pipeline penetrates the crack and further corrodes the pipeline. Also, if the adhesion is poor, the cracked repair material may peel off. Consequently, the use of conventional cementitious materials often makes the repaired pipeline less durable and requires repeated maintenance.

To overcome the inherent brittleness of cement-based materials, fiber-reinforced composites called Engineered Cementitious Composites (ECC) have been developed for spray repair. ECC exhibits high strain capacity greater than 3% under uniaxial tension. The high ductility of ECC is achieved by multiple tight cracks instead of the single crack characteristic of ordinary concrete. However, when compared to normal concrete, ECC mixtures generally have higher volume of cement and no coarse aggregate, so drying shrinkage can reach -1500 με at 28 days. When deformation is limited, enhanced shrinkage may result in microfractures. The presence of micro-cracks in aggressive environments may affect the durability of spray repairs. Examples of ECC are disclosed in the following patents.

US Patent No. 7,241,338 discloses a sprayable cement comprising hydraulic cement (such as Portland cement), non-Newtonian additives, adhesives, superplasticizers, discontinuous staple fibers, lightweight aggregates, and water sexual composition.

US Patent No. 7,572,501 discloses cementitious composites comprising cement (such as Portland cement), water, sand, fly ash, water reducers, and discontinuous short fibers such as polyethylene (PE) fibers. The rheology of the composition can be adjusted to provide composites that can be pumped, cast or sprayed.

US Patent No. 7,799,127 discloses a class of polyvinyl alcohol (PVA) fiber-reinforced early-strength ECC materials. The material includes hydraulic cement, a chemical accelerator mixture, polyvinyl alcohol fibers, a non-matrix interactive fracture initiator, one or more fine-grained aggregates, and a chemical dispersant mixture.

One of the goals of this creation is to help avoid the above deficiencies to some extent; and/or at least provide the public with a useful choice.

Other objectives of the present creation may become apparent from the following description, given by way of example only.

Any discussion of documents, acts, materials, devices, items or the like included in this specification is solely for the purpose of providing a context for this creation. It should not be taken as an admission that any or all of these matters formed part of the prior art basis or were common knowledge in the field relevant to the present creation because they existed prior to the priority date.

Creation Summary

This creation is a sprayable cementitious composition. According to an embodiment of the present creation, in the first aspect, the present creation provides a sprayable cementitious composition comprising the following: a composite adhesive, fibers and water; wherein the composite adhesive comprises a cement component and a buzuolan pozzolan component.

In some embodiments, the ratio of water to composite binder is from about 0.2 to about 0.5.

In some embodiments, the ratio of water to composite binder is from about 0.2 to about 0.4.

In some embodiments, the ratio of water to composite binder is about 0.3.

In some embodiments, the cement component includes hydraulic cement and a swelling agent.

In some embodiments, the swelling agent is calcium sulfoaluminate.

In some embodiments, the amount of swelling agent is from about 10 wt% to about 60 wt% based on the weight of the total cement components.

In some embodiments, the amount of swelling agent is about 20 based on the weight of the total cement components wt% to about 50 wt%.

In some embodiments, the bulking agent has an average particle size of from about 2 μm to about 500 μm or from about 10 μm to about 30 μm.

In some embodiments, the hydraulic cement comprises ordinary Portland cement.

In some embodiments, the amount of hydraulic cement is from about 1 wt% to about 80 wt% based on the weight of the total cement components.

In some embodiments, the amount of hydraulic cement is from about 20 wt% to about 80 wt% based on the weight of the total cement components.

In some embodiments, the amount of hydraulic cement is from about 50 wt% to about 80 wt% based on the weight of the total cement components.

In some embodiments, the amount of hydraulic cement is from about 60 wt% to about 80 wt% based on the weight of the total cement components.

In some embodiments, the cementitious component comprises reactive aluminosilicate, calcium carbonate, or mixtures thereof.

In some embodiments, the reactive aluminosilicate is a calcined clay.

In some embodiments, the reactive aluminosilicate is metakaolin.

In some embodiments, the calcium carbonate is limestone.

In some embodiments, the cement component comprises the reactive aluminosilicate in an amount from about 1 wt % to about 80 wt %, or about 30 wt % to about 60 wt %, or about 40 wt % to 50 wt %, based on the total cement component weight , calcium carbonate or mixtures thereof.

In some embodiments, the cement component includes the reactive aluminosilicate in an amount from 0 wt % to about 50 wt % or about 20 wt % to about 40 wt % or about 30 wt %, based on the total cement component weight.

In some embodiments, the cement component includes calcium carbonate in an amount from about 0 wt % to about 30 wt % or about 10 wt % to about 20 wt % or about 15 wt % based on the total cement component weight.

In some embodiments, the ratio of reactive aluminosilicate to calcium carbonate is 2:1.

In some embodiments, the cement component comprises about 10 wt% to about 50 wt% ordinary portland cement (OPC), about 20 wt% to about 40 wt% metakaolin, and about 10 wt% to about 20 wt% based on the total cement mixture weight limestone.

In some embodiments, the average particle size of the reactive aluminosilicate is from about 2 μm to about 40 μm or from about 2 μm to about 10 μm.

In some embodiments, the calcium carbonate has an average particle size of about 2 μm to about 100 μm or about 2 μm to about 20 μm.

In some embodiments, the amount of the buzuolan component is about 1 to about 3 times the amount by weight of the cement component.

In some embodiments, the amount of the buzuolan component is from about 2 times to about 3 times the amount of the cement component by weight.

In some embodiments, the amount of the buzuolan component is from about 2 times to about 2.5 times the amount of the cement component by weight.

In some embodiments, the buzuolan component comprises a material selected from the group consisting of fly ash, steel slag, granular blast furnace slag, diatomaceous earth, silica fume; calcined clay, such as metakaolin; calcined leaf rock , volcanic ash, pumice; organic matter rich in calcined silica, such as rice husk ash; and mixtures of any two or more thereof.

In some embodiments, the fly ash is selected from the group consisting of Type C fly ash, Type F fly ash, and mixtures thereof.

In some embodiments, the fibers are selected from the group consisting of polymeric fibers, inorganic fibers, metal fibers, carbon fibers, plant-based fibers, and mixtures of any two or more thereof.

In some embodiments, the polymeric fibers comprise polymeric materials selected from the group consisting of polyolefins, polyacrylic acids, polyesters, polyvinyl alcohols, polyamides, and any two or more thereof combine.

In some embodiments, the polymeric fibers are selected from the group consisting of polyethylene fibers, high tenacity polypropylene fibers, polyvinyl alcohol fibers, and mixtures of any two or more thereof.

In some embodiments, the amount of fibers is from about 0.1 v/v% to less than 4 v/v% or from about 1 v/v% to about 3 v/v, based on the total composition volume (ie, the volume of the composition including water). v% or about 1.5 v/v% to about 2.3 v/v%.

In some embodiments, the fiber length is about 4 mm to about 25 mm or about 6 mm to about 20 mm or about 8 mm to about 12 mm.

In some embodiments, the fiber diameter is from about 10 μm to about 150 μm or from about 10 μm to about 60 μm.

In some embodiments, the sprayable cementitious composition further comprises one or more components selected from the group consisting of superplasticizers, aggregates, tackifiers, and retarders.

In some embodiments, the amount of superplasticizer is from about 0.1 wt % to 10 wt %, or from about 0.3 wt % to about 3 wt %, or from about 0.5 wt % to about 1.5 wt %, based on the total composition weight.

In another aspect, the present creation provides a sprayable cementitious composition comprising the following: a composite adhesive, fibers and water; wherein the composite adhesive comprises a cement component and a pozzolanic component, and wherein the sprayable cementitious composition The characteristic composition when cured achieves one or more properties selected from the group consisting of: (i) a tensile strength of at least about 2.50 MPa, (ii) a tensile strain capacity of at least about 3% at 28 days, ( iii) a crack width of less than about 100 μm at <2% ε, and (iv) a maximum expansion of at least about 1210 με.

In yet another aspect, the present invention provides a method of preparing a sprayable cementitious composition, the method comprising: (i) providing an adhesive composition comprising a cement component and a pozzolanic component, (ii) mixing the binder composition with water to form a wet mixture, (iii) adding fibers to the wet mixture.

In some embodiments, the method further includes mixing the cement component and the buzuolan component to obtain an adhesive composition.

In some embodiments, a superplasticizer is added to the water prior to step (ii).

In yet another aspect, the present invention provides a method of repairing and/or refinishing a building structure, the method comprising the steps of: (i) providing the sprayable cementitious composition of the present invention; (ii) on the surface of the building structure overspraying the cementitious composition to at least partially coat the surface with the cementitious composition; and (iii) setting the cementitious composition on the surface.

In some embodiments, spraying step (ii) is performed by a manual spraying system or an automated spraying system.

In some embodiments, the building structure is a pipeline.

In some embodiments, the surface is the inner surface of the pipeline.

In some embodiments, the pipeline is trimmed to extend the life of the pipeline, increase the bearing capacity of the pipeline, and/or strengthen the pipeline.

In another aspect, the present invention provides the use of the sprayable cementitious composition of the present invention for repairing and/or finishing building structures.

In some embodiments, the building structure is a pipeline.

In another aspect, the present creation provides an intervention mixture for preparing the sprayable cementitious composition of the present creation, the intervention mixture comprising a composite binder and fibers; wherein the composite binder comprises a cement component and a As the Lan component.

In another aspect, the present creation provides a sprayable cementitious composition for preparing the present creation of the present invention, the method comprising: (i) providing an intervention mixture of the present invention, (ii) mixing the intervention mixture with water to form a sprayable cementitious composition.

In another aspect, the present creation provides a spraying system comprising: a spraying body having a chamber and a nozzle connected to the chamber; and the above-mentioned sprayable can be housed in the chamber and adapted to be sprayed through the nozzle Spray-on cementitious composition.

In another aspect, the present creation provides a building structure comprising a repaired and/or reconditioned building structure and a repair layer made from the above-mentioned sprayable cementitious composition and disposed on the surface of the building structure .

In certain embodiments, the repair layer is formed by spraying the sprayable cementitious composition onto the surface of the building structure using a manual spray system or an automated spray system.

It may also be broadly said that the creation consists of individual or collective parts, elements and features mentioned or indicated in the specification of this application and any or all combinations of any two or more of such parts, elements or features, and Where reference is made herein to specific integers having known equivalent integers in the art relevant to the present invention, such known equivalent integers are deemed to be incorporated herein as if individually set forth.

In addition, in the case where the features or aspects of this creation are described in the manner of the Markush group, those skilled in the art should understand that this creation also uses any individual Markush group. members or subgroups of members are described.

"(s)" after a noun as used herein means the plural and/or singular form of that noun.

The term "and/or" as used herein means "and" or "or" or both.

The term "comprising" as used in this specification means "consisting at least in part of". When construed in this specification including the term "package "Comprising" may also have features other than one or more of the preceding features of the term. Related terms such as "comprise/comprises" will be interpreted in the same way.

It is intended that references to ranges of numbers disclosed herein (eg, 1 to 10) also include all reasonable numbers within that range (eg, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10) and any ranges of reasonable values within that range (eg, 2 to 8, 1.5 to 5.5, and 3.1 to 4.7), and therefore, all sub-sections of all ranges expressly disclosed herein are hereby expressly disclosed scope. These are merely examples of what is specifically desired, and all possible combinations of numerical values between the lowest and highest enumerated values are deemed to be expressly recited in this application in a similar fashion.

While the creation is broadly as defined above, those skilled in the art will understand that the creation is not so limited and that the creation also includes embodiments of which the following description gives examples.

100: Raw Concrete Pipe

8”牛皮紙管 102:

8" Kraft Paper Tube

6”牛皮紙管 103:

6" Kraft Paper Tube

4.5”牛皮紙管 104:

4.5" Kraft Paper Tube

105: SDMCC

200: spray body

201: Chamber

202: Nozzle

300: Restored and/or refurbished building structures

301: Repair Layer

302: Building Structures

8”牛皮紙管、元件103為

6”牛皮紙管、元件104為

4.5”牛皮紙管及元件105為SDMCC；圖11繪示混凝土管及經SDMCC修復管之高峰載荷與位移之間的關係；圖12繪示具有一腔室201及一連接至該腔室201之噴嘴202的噴塗本體200；及圖13繪示經修復且/或經修整的建築結構300，其包含一建築結構302及一修復層301。 The present creation will now be described with reference to the drawings in which: Figure 1 depicts SDMCC prepared with OPC and CSA-K cement (where CSA-K accounts for 7 wt %, 10 wt % and 13 wt % of the composite binder, respectively ) shrinkage/expansion; Figure 2 shows the shrinkage/expansion of SDMCC prepared with OPC and LC3/CSA-K cement (where CSA-K accounts for 10wt% and 13wt% of the composite binder, respectively); Figure 3 shows the use of CSA - Shrinkage/expansion of SDMCC prepared by R cement (in which anhydrite accounts for 0wt%, 10wt%, 15wt% and 20wt% of CSA-R, respectively); Figure 4 shows the maximum allowable expansion of SDMCC for repairing C40 concrete pipes ; Figure 5 shows the average strain of the steel ring measured by 3 strain gauges for SDMCC prepared with LC3/CSA-K cement and CSA-K cement (where CSA-K accounts for 13 wt% of the composite binder); Figure 6 The residual interfacial pressure between the steel ring and the SDMCC prepared with LC3/CSA-K cement and CSA-K cement (where CSA-K accounts for 13 wt% of the composite binder) is shown; Fig. 7 shows in Fig. 1 and Fig. 2 28-day tensile stress-strain behavior of the compositions shown; Figure 8 depicts the ultimate tensile strength and strain capacity of SDMCC prepared with OPC, LC3 and LC3/CSA-K cements after 7 wet-dry cycles self-healing; Figure 9 shows permeability coefficients tested at day 14 for SDMCC prepared with OPC and LC3/CSA-K cement after sample pre-rupture at 28 days; Figure 10 shows pipe repair cast with kraft paper tubes scheme, wherein element 100 is a raw concrete pipe, element 102 is

8" Kraft paper tube, element 103 is

6" kraft paper tube, element 104 is

4.5" kraft paper tube and element 105 is SDMCC; Figure 11 shows peak load versus displacement for concrete and SDMCC repaired tubes; Figure 12 shows a chamber 201 and a nozzle connected to the chamber 201 202 ; and FIG. 13 depicts a repaired and/or refurbished building structure 300 , which includes a building structure 302 and a repair layer 301 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The authors have unexpectedly discovered SDMCCs with advantageous properties compared to conventional cements and concretes. For example, SDMCC can exhibit expansion and strain hardening behavior upon curing.

Accordingly, in one aspect, the present creation provides an SDMCC comprising the following: a composite binder, fibers, and water; wherein the composite binder comprises a cement component and a Bozuolan component. The sprayable cementitious composition can be used, for example, to repair and/or trim pipelines.

The cement component includes hydraulic cement, and may further include additional materials such as swelling agents, reactive aluminosilicates, and/or calcium carbonate.

The SDMCC may further contain other components such as superplasticizers, aggregates and/or other additives.

hydraulic cement

Hydraulic cement is a material that sets and hardens when mixed with water. Hydraulic cements include, but are not limited to, portland cement, blended portland cement, phosphate cement, and belite cement (dicalcium silicate). Mixtures of any two or more thereof are also contemplated. Preferably, the hydraulic cement is Portland cement.

Portland cement is a finely ground powder produced from ground clinker consisting essentially of hydraulic calcium silicate. The cement may contain up to about 5% gypsum. The amount of gypsum present affects the setting time. ASTM C 150 Portland Cement Standard Specification defines Portland cement standards, which define eight types of Portland cement: Type I, Type IA, Type II, Type IIA, Type III, Type IIIA, Type IV, and Type V type. Type I cement is a general purpose ordinary Portland cement (OPC) suitable for all applications that does not require the special properties of other types. Type III cement is chemically and physically similar to Type I cement, except that it is more finely milled to produce earlier strengths.

The cement component may comprise hydraulic in an amount from about 1 wt % to about 80 wt %, or about 20 wt % to about 80 wt %, or about 50 wt % to about 80 wt %, or about 60 wt % to about 80 wt %, based on the total cement component weight cement.

In some embodiments, the cement component comprises reactive aluminosilicates such as calcined clays and/or calcium carbonates such as limestone. Advantageously, replacing part of the hydraulic cement with reactive aluminosilicate and/or calcium carbonate provides a more environmentally friendly composition by reducing the amount of carbon released during the manufacturing process.

SDMCCs containing reactive aluminosilicates and/or calcium carbonates may provide other advantages. For example, limestone calcined clay cement (LC3) slurries have been found to have a finer pore structure than slurries made with OPC. Advantageously, the pore refinement provides excellent resistance to chloride ingress and good performance in the presence of sulfates, which is especially important for complex environments in pipelines.

In addition, it has been unexpectedly found that compared to prior art ECC prepared with OPC, SDMCC containing LC3 has larger strain capacity and smaller crack width. The reduced fracture width results in lower permeability. Such a situation may, for example, prevent the original piping from being corroded by the fluid. Larger strain capacity SDMCCs are expected to have larger deformability. Such a situation may, for example, result in a repaired tube with higher load and deflection capacity.

The cementitious mixture may comprise the reactive aluminosilicate, calcium carbonate, or mixtures thereof in an amount from about 1 wt % to about 80 wt %, or from about 30 wt % to about 60 wt %, or from about 40 wt % to 50 wt %, based on the weight of the total cement components . For example, the cement component may comprise the reactive aluminosilicate in an amount from 0 wt % to about 50 wt % or about 20 wt % to about 40 wt % or about 30 wt %, based on the total cement component weight. For example, the cement component may comprise calcium carbonate in an amount from about 0 wt % to about 30 wt % or about 10 wt % to about 20 wt % or about 15 wt %, based on the total cement component weight. In some embodiments, the ratio of reactive aluminosilicate to calcium carbonate is 2:1.

In some embodiments, the average particle size of the reactive aluminosilicate is from about 2 μm to about 40 μm or from about 2 μm to about 10 μm. In some embodiments, the calcium carbonate has an average particle size of about 2 μm to about 100 μm or about 2 μm to about 20 μm.

In some embodiments, the cement component comprises about 10 wt % to about 50 wt % OPC, about 20 wt % to about 40 wt % metakaolin, and about 10 wt % to about 20 wt % limestone, based on the total cement mixture weight.

In some embodiments, a portion of the hydraulic cement may be replaced by mining tailings. For example, the cement component may include mining tailings in an amount from about 1 wt% to about 30 wt% based on the total cement component weight.

Bulking agent

Swelling agents are materials that enhance SDMCC swelling during the hydration process. In some embodiments, swelling agents can be used to reduce shrinkage that occurs during curing of the composition. In other embodiments, swelling agents may be used to provide SDMCCs that expand during curing. Advantageously, enhanced SDMCC inflation reduces systole risk of rupture.

Expansion agents can be used to adjust the expansion characteristics of the SDMCC such that when applied to the inner surface of the pipeline and cured, the SDMCC exerts an expansion force on the inner surface of the pipeline. The expansion force reduces any space between the SDMCC and the inner surface and increases the mechanical friction therebetween. Advantageously, the increased mechanical friction can increase the adhesion between the SDMCC and the inner surface. Thus, the repaired or trimmed pipeline may have higher load and deflection capacity than the original main pipe. In addition, the increased adhesion may reduce peeling of the SDMCC from the surface and wrinkling and even buckling of the repair layer during post-repair service. The controlled expansion force exerted by the SDMCC on the main pipe can cause the repair layer to couple to the main pipe wall and cause a combination of structural and functional repairs, rather than just functional repairs, such as repairing water leaks. However, those skilled in the art will appreciate that in some embodiments, excessive expansion should be avoided as it may cause deformation of the surface to which the SDMCC is applied or even damage to the main pipe.

In addition to applying pressure to the line, the expansion characteristics also differentiate SDMCC from known sprayable ECCs, which typically have large drying shrinkages of about -1500 με after 28 days. Intumescent SDMCC reduces the risk of constrained contraction rupture, further increases the durability of the repaired pipeline, and reduces the risk of post-repair leakage.

Those skilled in the art will understand that the preferred expansion characteristics of the SDMCC depend on various factors such as the diameter and tensile strength of the main pipe to be repaired or trimmed (whether or not the main pipe is under confining pressure) and the desired thickness of the SDMCC. In some embodiments, the SDMCC expands to at least about 1200 με. In some other embodiments, the SDMCC expands to at least about 3000 με. The maximum SDMCC expansion may be, for example, about 3000 με, about 3375 με, about 4000 με, or about 4450 με.

Preferred expansion agents include calcium aluminate cement (CAC) and calcium sulfoaluminate cement (CSA). Preferably, the bulking agent is CSA. The amount of CaSO ₄ ·nH ₂ O in the CSA is preferably about 1 wt % to 50 wt %, where n can be 0, 0.5, 1, or 2, based on the weight of the CSA.

The composite binder may comprise from about 10 wt % to about 60 wt % based on the weight of the total cement components Bulking agent in an amount from or about 20 wt% to about 50 wt%. In some embodiments, the bulking agent has an average particle size of from about 2 μm to about 500 μm or from about 10 μm to about 30 μm.

Bu Zuolan

Bu Zuolan is a siliceous or siliceous and aluminum material usually provided in finely pulverized form. Bu Zuolan alone has little or no cementitious properties, however, in the presence of water, Bu Zuolan reacts with calcium hydroxide released by the hydration of hydraulic cement to form hydrated calcium silicate and other cementitious compounds. Advantageously, Bu Zuolan can improve the adhesive fracture toughness of cementitious materials, resulting in higher ductility of cured SDMCC. Bu Zuolan can also be used to adjust the rheology of SDMCC. Advantageously, the SDMCC rheology can be adjusted to improve the pumpability and/or sprayability of the composition.

In general, any siliceous or siliceous and aluminum material that reacts with calcium hydroxide in the presence of water may be suitable for use in the adhesive. Examples of suitable slag include, but are not limited to, fly ash, steel slag, granular blast furnace slag, diatomaceous earth, silica fume; calcined clays, such as metakaolin; calcined phyllolites, pozzolans, pumice; rich calcined silica of organic matter, such as rice husk ash; and mixtures of any two or more thereof. Preferably, the Bu Zuolan component comprises fly ash as defined, for example, in ASTM C618. In some embodiments, the fly ash is Type C fly ash and/or Type F fly ash.

In some embodiments, the Bu Zuolan component includes silica fume. Advantageously, silica fume can increase SDMCC compressive strength and/or improve fiber/matrix interface bonding.

The composite binder may include the buzuolan component in an amount from about 0 times to about 3 times the weight of the cement component. Preferably, the composite binder comprises the buzuolan component in an amount from about 1 to about 3 times, more preferably from about 2 to about 3 times, more preferably from about 2 to about 2.5 times the weight of the cement component.

fiber

The fibers are intended to strengthen the cured SDMCC. Suitable fibers can be selected based on various characteristics of the fibers including desired cost, mechanical properties, physical properties, and bonding properties. SDMCC properties can be affected by factors such as fiber length, diameter, chemical composition, stiffness, density, and strength. fiber can be Select to transport the load across the crack when loading the composite material beyond the elastic stage. Its load-load behavior can be tuned to balance fiber breakage and fiber slipperiness, ie, controlled fiber bridging behavior. Excessive fiber breakage or fiber slipperiness is undesirable during imposing loads on a composite because it can limit composite ductility or cause crack widths that are too large to compromise the durability of the composite. Advantageously, fibers can improve the strain hardening and tensile resistance of the composite and limit crack width.

Fibers suitable for use in SDMCC include, but are not limited to, polymer fibers, inorganic fibers (eg, basalt fibers and glass fibers), metal fibers (eg, steel fibers), carbon fibers, plant-based fibers (eg, cellulose fibers and lignocelluloses) fibers) and mixtures of any two or more thereof. Preferably, the fibers are polymeric fibers, that is, fibers made of materials such as polyolefins (eg polyethylene or polypropylene), polyacrylic acids, polyesters, polyvinyl alcohols, polyamides (eg nylon), or any two or more thereof. Fibers composed of a combination of polymer materials. More preferably, the fibers are polypropylene fibers, more preferably high tenacity polypropylene fibers. In some embodiments, the fibers are discontinuous staple fibers.

The upper limit of fiber concentration is specified by the pumpability and sprayability requirements, and the lower value is specified by the ability to provide strain hardening (ductility) behavior relative to brittle or quasi-brittle behavior. For example, the fibers may be from about 0.1 v/v% to less than 4 v/v%, or from about 1 v/v% to about 3 v/v%, or about 1.5v/v% to about 2.3v/v% is present. In some embodiments, the fiber length is about 4 mm to about 25 mm or about 6 mm to about 20 mm or about 8 mm to about 12 mm. In some embodiments, the fiber diameter is from about 10 μm to about 150 μm or from about 10 μm to about 60 μm.

Superplasticizer

In some embodiments, the SDMCC further comprises a superplasticizer, also known as a superplasticizer. Superplasticizers can be added to SDMCC to affect composition rheology. Advantageously, the superplasticizer can reduce the amount of water required to maintain the pumpability and sprayability of the SDMCC.

Thus, superplasticizers are typically added to the SDMCC in amounts effective to achieve a composition with the desired pumpability and sprayability. Those familiar with the art should understand that achieving the desired pumpability The amount of superplasticizer required for delivery and sprayability depends on other components of the composition such as the moisture content of the composition. For example, the superplasticizer may be included in the SDMCC in an amount of about 0.1 wt % to 10 wt %, or about 0.3 wt % to about 3 wt %, or about 0.5 wt % to about 1.5 wt %, based on the total composition weight.

In general, any superplasticizer known in the art is suitable for use in SDMCC. Such superplasticizers include, but are not limited to, sulfonated melamines (such as sulfonated melamine formaldehyde condensates), sulfonated naphthalenes (such as sulfonated naphthalene formaldehyde condensates), polycarboxylate ethers (such as ADVA ^® 190), modified lignosulfonates and mixtures of any two or more thereof.

Aggregate

The SDMCC may further comprise aggregates such as sand, grindstone and lightweight aggregates. Incorporation of lightweight aggregates reduces SDMCC density. Incorporation of lightweight aggregates may also allow increased thickness to be sprayed, particularly on horizontal top surfaces. If the amount of lightweight aggregate is substantial, the particle size becomes critical, otherwise strain hardening cannot be achieved. In general, the average particle size is from about 10 μm to about 1000 μm or from about 10 μm to about 200 μm or from about 30 μm to about 100 μm.

Lightweight aggregates may include, but are not limited to, ground rubber (eg, from scrap tires), hollow glass spheres, floating beads, expanded mica, and microballoons (eg, glass, ceramic, or polymer microballoons).

In addition to or in place of the lightweight aggregate, the SDMCC may further contain air bubbles. Gases can be introduced during processing of the cementitious composition by physical means such as foaming or aeration. Alternatively, the gas can be chemically induced, for example, as hydrogen gas generated by the reaction of aluminium powder with an alkaline composition or by the reaction of Si-H functional silane with water. In some embodiments, stabilizing substances are added to assist in preventing coalescence of adjacent bubbles. In some embodiments, the volume percentage is limited to provide a cured density of about 1400 kg/m ³ or higher, preferably 1500 kg/m ³ or higher. If extensive coalescence occurs in large voids, the strength properties of the composite, specifically strain hardening behavior, may be compromised. Air bubbles can be used in combination with other lightweight aggregates. Advantageously, the bubble volume fraction in these formulations can be kept small to minimize coalescence. For example, in a composite with a target density of 1300kg/ ^m , a gas or gas precursor can be added to achieve a density of about 1600kg/ ^m or higher, and other lightweight fillers are added to reduce the density to the target scope.

Other additives

The SDMCC may further contain other additives known in the art, such as tackifiers and/or retarders.

For example, the viscous agent may be a cellulose derivative such as hydroxypropyl methylcellulose (HPMC). The adhesive may be from about 0 wt % to about 1 wt % or from about 0.03 wt % to about 0.5 wt % or from about 0.05 wt % to about 0.2 wt %, based on the total adhesive weight (ie, the weight of the composition excluding water) The amount is included in the SDMCC. The adhesive enhances the ability of the composite to build up thickness on the matrix, and also helps the fibers to be uniformly dispersed in the matrix.

SDMCC may contain retarders. Conventional retarders can be used. A preferred retarder is citric acid which is advantageously compatible with CSA use. The retarder can be included in an amount from about 0.01 wt % to about 10 wt %, or from about 0.1 wt % to about 2 wt %, or from about 0.2 wt % to about 1.5 wt %, based on the total binder weight. Retarders extend the working time of the SDMCC during the spraying process. However, those skilled in the art will appreciate that excess retarder can reduce SDMCC strength and ductility.

water

The amount of water in the SDMCC affects various properties of the composition. The moisture content should be sufficient to obtain a pumpable and sprayable composition. In general, higher water content reduces viscosity and improves sprayability, while lower water content improves cohesion and allows for thicker applications. The amount of water required to provide a pumpable and sprayable composition can be readily determined by routine experimentation and can be reduced by including a superplasticizer as discussed above.

In some embodiments, the water to binder ratio is from about 0.2 to about 0.5. Preferably, the water to binder ratio is from about 0.2 to about 0.4, more preferably about 0.3.

Preparation of cementitious compositions

The SDMCC of the present creation can be prepared by conventional techniques. Ingredients can be mixed with water individually Or certain ingredients can be premixed. In some embodiments, water is added to a premix of dry binder ingredients to obtain a wet mix with fibers added to the wet mix. In some embodiments, the superplasticizer is mixed with water to form a solution that is added to a premix of dry binder ingredients to obtain a wet mix to which fibers are added. In some other embodiments, the dry ingredients may be provided in a "ready to mix" composition that is mixed with water prior to use to form the SDMCC, such as a premix of dry binder ingredients and fibers.

Repair and trim pipelines

The SDMCC of this creation can be used to repair pipelines such as gravity pipelines or pressure pipelines, specifically underground gravity pipelines or pressure pipelines. These lines are found in various applications such as water pipes, drain pipes, sewage pipes and oil pipes. For example, SDMCC can be used in excavation-free pipeline repair methods. The method of repairing the pipeline of the present invention is compatible with various pipe geometries such as pipes with circular or non-circular cross-sections, pipes with narrow or wide diameters, straight pipes or curved pipes.

The creator also confirms that the SDMCC of this creation can be used to trim the pipeline. In contrast to repair methods that aim to restore the original function of a damaged main, trim refers to methods in which the characteristics of the pipeline are enhanced. For example, the pipeline may be trimmed to extend the life of the pipeline, increase the bearing capacity of the pipeline, and/or strengthen the pipeline. In some embodiments, the pipeline is trimmed for seismic strengthening of the pipeline. For this purpose, SDMCC can be applied to pipelines to reduce the risk of leakage or contamination of drinking water or groundwater caused by seismic events.

The method of repairing or trimming the pipeline of the present invention prevents common failures that occur in pipelines repaired or trimmed by other methods such as CIPP, slip lining or spiral wound lining methods, or other methods of spray lining with known materials model. Common failure modes that can be avoided include local buckling, lining or pipeline rupture, water leakage, and lining or pipeline corrosion.

A method of repairing or trimming a pipeline includes providing the SDMCC in the form of a wet mixture, applying the wet mixture and curing the mixture to at least a portion of the surface of the pipeline, such as the inner wall of the pipeline. In some embodiments, SDMCC is applied to the entire inner surface of the pipeline length. Advantageously, coating the entire inner surface can substantially create a new inner tube. Continuous spraying of cementitious material along the length of the degraded line provides a reduced number of The linker and in some embodiments do not have an inner coating of the linker. Joints are often a weak point in pipelines, and thus, advantageously, reducing the number of joints in a repaired pipeline can extend the useful life of the pipeline. Pipelines with a continuous inner coating with a reduced number of joints or without joints are also less prone to leaks, including under hazardous conditions such as earthquakes.

The cementitious composition can be applied to the surface of the pipeline by conventional methods. SDMCC can be applied by manual spray systems or automated spray systems. For example, SDMCC can be applied manually by pneumatically spraying the composition onto a surface at high velocity through a nozzle. Alternatively, SDMCC can be applied by an automated centrifugal spray system that sprays the material onto the inner surface of an existing pipeline.

The cementitious composition is fluid during pumping, but coagulates after spray application to the surface. The rate of setting should be fast enough to allow the thickness to build up against gravity. The SDMCC of the present creation may be about 10 mm to about 50 mm thick when sprayed onto horizontal or vertical surfaces including the top surface. In some embodiments, the SDMCC is about 20 mm to about 40 mm thick when sprayed onto a horizontal or vertical surface. In some embodiments, the SDMCC is about 20 mm to about 30 mm thick when sprayed onto a horizontal or vertical surface.

The SDMCC of this creation can be used to repair and trim the pipeline. However, those skilled in the art will appreciate that the SDMCC of the present creation can be used to repair and/or refurbish other building structures. In particular, building structures in which one or more of the improved properties described herein are beneficial. For example, suitable building structures may include tunnels, culverts, manholes, bridges, decks, and roads.

The following non-limiting examples are provided to illustrate the present creation and in no way limit its scope.

example

1. Material composition and processing

Exemplary mixtures are listed in Table 1. The cement was Portland Cement Type I (PC1) from Lafarge Cement Co., MI, USA. Two types of expansive cements from CTS Cement Manufacturing Corp. and from Royal White Cement Inc were used and are defined as CSA-K and CSA-R, respectively. metakaolin (MK) is Sikacrete® M-100 from Sika Corporation, NJ, USA. Anhydrite was No. 1 Terry-Alba from USG. Limestone (LS) was Snowhite® 12-PT from Omya Canada Inc. Fly ash (FA) is a Class C fly ash from Boral Material Technologies Inc with a size distribution of 10 μm to 100 μm. The superplasticizer (SP) was AVDA® 190 from GCP Applied Technologies. Hydroxypropyl methylcellulose (HPMC) adhesive was from Fisher Scientific. The amount of polypropylene (PP) fibers is 2% volume fraction, of which the diameter is 12 μm, the length is 10 mm, the Young's modulus is 6 GPa and the tensile strength is 850 MPa, and the PP fibers are from Saint-Gobain Brazil The Brasilit.

The nomenclature in Table 1 reflects the adhesive composition. OPC and LC3 refer to binders prepared from ordinary Portland cement and limestone calcined clay cement, respectively. K07, K10 and K13 refer to CSA-K to binder ratios of 7 wt %, 10 wt % and 13 wt %. R13-C0, R13-C10, R13-C15 and R13-C20 represent the ratio of CSA-R and anhydrite to binder of 13wt%, wherein the ratio of anhydrite is 0wt%, 10wt%, 15wt% and 20wt%. The wt% ratio of PC1, MK and LS in LC3 cement is 55%, 30% and 15%.

SDMCC was prepared by mixing all dry ingredients (PC1, CSA, anhydrite, MK, LS, FA and HPMC) in a drum mixer for 10 minutes. Water and SP were added gradually and mixed for 6 minutes. The PP fibers were added last, followed by mixing for 6 minutes.

2. The sprayability of the cementitious composition

The new feature of sprayable (often referred to as "spray") ECC is critical. Sprayable cementitious compositions require high initial deformability for pumping, fast build-up capability when sprayed onto a substrate, and optimal rest time. The settling time, defined as the time interval from the completion of mixing to the start of spraying, should be long enough to accommodate the time required for pumping and short enough to obtain the desired stack thickness when spraying.

The composition of SDMCC is the same as that of LC3-K13 in Table 1, the difference is the different SP content. Compared to prior art sprayed ECC containing 2v/v% PVA fibers, the present creation SDMCC employs 2v/v% PP fibers, which are advantageously less expensive than PVA fibers. However, at the same dose and fiber length, the number of PP fibers (12 μm) in the SDMCC was 10.56 times the number of fibers (39 μm) in the prior art sprayed PVA-ECC. Large numbers of small diameter fibers require careful control of the new rheology of sprayable SDMCC.

A CARROUSEL pump from Quikspray Inc. and a multi-jet magnetic pole spray gun were used for spraying in the examples described below. The multi-jet magnetic pole spray gun is particularly suitable for spraying cementitious materials with reinforcing fibers. The materials were mixed in a Hobart mixer and then pumped by a CARROUSEL pump. After passing through a 1.25" (31.75 mm) diameter material hose and to a multi-jet magnetic pole spray gun, the SDMCC was sprayed onto the plywood substrate at 560 kPa air pressure. Spray testing included spraying onto the substrate from both vertical and top orientations.

The optimum superplasticizer content was determined to be 0.8 wt% of the composite adhesive using a series of flow tests with varying amounts of superplasticizer. For the vertical plywood substrate spray test, the stack thickness was 15 mm after a 20 minute rest time. For vertical plywood substrates, when the standing time is 40 minutes, the maximum Large stack thicknesses may reach 50mm. For the top substrate, a maximum thickness of 25mm is possible after a 20 minute rest time.

Although the number of fibers in the SDMCC was 10.56 times the number of fibers in the prior art sprayed PVA-ECC, the sprayed SDMCC was found to have good atomization, allowing the material to be uniformly sprayed onto the substrate. SDMCC exhibits little springback and does not drip or sag after being sprayed onto a substrate, exhibiting numerous advantages over conventional coating materials.

3. Inflation feature

Samples for measuring shrinkage/expansion were cast into a mold (25 x 25 x 300 mm). Shrinkage/expansion measurements were made as early as possible after demolding without damaging the specimen and were marked as "zero time" for deformation. For the mixtures in Table 1, demold times were 20 hours for OPC; 10 hours for K07; 5 hours for K10, K13 and LC3-K13; 8 hours for LC3-K10; , R13-C15 and R13-C20 for 3 hours. Specimens were stored at 20°C ± 2°C and 40% ± 5% relative humidity (RH). Specimen length variation is tested according to ASTM C490/C490M-17.

3.1 Drying shrinkage/expansion

Shrinkage/expansion versus time curves for the compositions in Table 1 are shown in Figures 1-3, where a negative sign (on the y-axis) indicates contraction and a positive sign indicates expansion. Table 2 lists the characteristic values of shrinkage/expansion at 28 days. For SDMCC prepared with OPC, shrinkage increased continuously to -1434 με at 28 days. This relatively large shrinkage may lead to cracking under restricted conditions, thereby reducing material durability. SDMCC with CSA-K showed initial expansion followed by contraction. The maximum expansion occurs over a period of about 2 days. The maximum expansion amplitudes of compositions K07, K10 and K13 were 779 με, 2418 με and 3756 με, which varied with the CSA-K ratio. However, with 7 wt% CSA-K cement in the composite binder, the SDMCC still showed a shrinkage of -832 με at 28 days. The expansions of K10 and K13 at 28 days were 1139 με and 2026 με, respectively. The ECC expansion using LC3 is a bit lower than the ECC expansion using OPC. The expansion of LC3-K10 and LC3-K13 was 838 με and 1722 με.

CSA cement type can also affect the magnitude of expansion. CSA-R is a CSA binder with less CaSO4 compared to CSA _- K. Even when the CSA-R content was 13 wt% of the composite binder (R13-C0), the shrinkage of R13-C0 at 28 days was -834 με and showed no swelling. CSA-R replacement with anhydrite increased, shrinkage decreased, and R13-C20 had a 489 με expansion at 28 days. Without wishing to be bound by theory, it is believed that the amount of CaSO4 ₍ gypsum or anhydrite) in the CSA cement affects ettringite production. Eettringite is the main expansive hydration product of CSA cement.

3.2 Minimum expansion

Assuming linear material constitutive behavior, the pressure due to expansion can be expressed as: p = E ₁ ε ₁ - E ₂ ε ₂ (1)

where p is the pressure exerted by the dilatant SDMCC; ε ₁ is the maximum expansion of the SDMCC; ε ₂ is the difference between the maximum expansion and the residual strain at 28 days; the effective mode between the time when E ₁ is zero and the maximum expansion time Number and; E ₂ is the effective modulus between the maximum expansion time and 28 days. ε ₁ and ε ₂ can be tested by drying shrinkage/expansion testing according to ASTM C490/C490M-17 and the values are listed in Table 2. E1 and E2 _are the effective _moduli affected by stress relaxation and timing development. The creep during the early period (3 days ago) was more pronounced than the late period (3-28 days). In addition, the elastic modulus in the early stage is small, even with fast-hardening SDMCC materials.

Assuming E ₁ = kE ₂ , the pressure can also be expressed as: f =( kε ₁ - ε ₂ ) E ₂ (2)

where k is defined as the effective modulus coefficient. k is determined by the combined effect of material elastic modulus development and boundary constraints. Advantageously, f should be greater than zero in order to ensure that the SDMCC produces a coupling action against the main pipe. In other words, kε ₁ - ε ₂ should be greater than 0. According to Zhu H. et al., Double feedback control method for determining early-age restrained creep of concrete using a temperature stress testing machine. Materials, 2018, 11(7), 1079, it seems reasonable to assume k = 0.5.

For the mixtures in Table 2, the maximum expansion and the expansion after 28 days of OPC are different from K07, K10 and K13; however, the difference between the maximum expansion and the 28 day expansion of OPC, K07, K10 and K13 (ie ε ₂ ) similar. It is found experimentally that the ε _{2 of the OPC-based SDMCC is about 1531 με and the ε 2 of} the LC3-based SDMCC is 605 με. Therefore, for an OPC-based SDMCC, the maximum expansion ε ₁ = ε ₂ / k is preferably at least 3062 με (1531/0.5) to provide the desired coupling effect. The maximum expansion of SDMCC dominated by LC3 is preferably at least 1210 με (605/0.5).

3.3 Maximum allowable expansion

As explained above, while SDMCC expansion is desirable, excessive expansion should be avoided as it may cause damage to the main pipe. According to the elastic theory of steel rings (Hossain AB, Weiss J. Assessing residual stress development and stress relaxation in restrained concrete ring specimens. Cement and Concrete Composites, 2004, 26(5): 531-540), the elastic pressure exerted by SDMCC on the main pipe can be expressed as equation (3) and the maximum elastic stress of the main pipe can be calculated by equation (4):

_△ σmax =△ p _elastic C _{3 R} (4)

where Δεex is the expansion of the _SDMCC ; EC and ES are the elastic moduli of the main pipe and the SDMCC ; and _{C 1 R} , _C 2 _R , C _{3 R} can be assumed for as in equations (5) to (7) is shown to be constant for a given geometry:

where v _C and v _S are the Poisson's ratio of the main pipe and the _SDMCC ; RIS and R _OS are the inner and outer radii of the SDMCC, respectively; and R _IC and R _OC are the inner and outer radii of the main pipe, respectively.

Equations (3) to (7) indicate the maximum tensile strength in the main pipe, main pipe inner diameter (ID), SDMCC expansion, and material mechanical properties as a function of SDMCC thickness. C40 concrete pipes with different diameters [ID=48" (1219mm), 60" (1524mm) and 90" (2286mm)] are used as examples. The tensile strength is 5MPa and the elastic modulus is 40GPa. During zero time and maximum expansion time The mean SDMCC modulus of elasticity is assumed to be 5GPa. The Pason's ratio of the main pipe and SDMCC is assumed to be equal to 0.18. Assuming that the relaxation stress during the early (0-3 days) period is 0.5 of the total elastic stress, the maximum allowable resistance in the main pipe is The maximum allowable expansion at a tensile stress of half the tensile strength (2.5 MPa) can be calculated using equations (3) to (7).

Figure 4 plots the maximum allowable expansion of SDMCC used to repair C40 concrete pipes, and the characteristic values are listed in Table 3. The tensile stress in the main pipe increases with the thickness of the SDMCC. For a 48" (1219mm) main pipe repaired by 1.5" (38mm) thick SDMCC, the maximum allowable expansion is 3375με, which is less than the maximum allowable expansion of K13 (3756με). Therefore, when used to repair 48" (1219mm) pipe, the thickness of K13 should not exceed 1" (25mm). Thickness may be increased to repair larger diameter tubes. For example, for a 90" (2286 mm) tube repaired with a 2" (51 mm) thick SDMCC, the maximum allowable expansion is 4450 με.

Pipelines are usually buried underground under confining pressure conditions. The confining pressure reduces the tensile stress of the main pipe caused by the expansion of the SDMCC. Assuming a confining pressure of 0.3 MPa as shown in Table 3, the maximum allowable expansion is significantly increased compared to the maximum allowable expansion of the pipeline without the confining pressure.

In the case of confining pressure, K13 can also be used to repair 48" (1219mm) pipeline with 2" (51mm) thickness SDMCC. Without wishing to be bound by theory, the authors propose a maximum allowable expansion of SDMCC for repairing pipelines of 3000 με and 4000 με without and with confining pressure, respectively.

table 3

3.4 Restricted Expansion Test Using Steel Rings

Concrete was cast around the steel ring in the annular zone according to the Restricted Shrinkage Test Method ASTM C1581/C1581M-18a. The strain caused by the shrinkage of the concrete exerting pressure on the steel ring is monitored and used to calculate the interface pressure.

The expanded steel ring test method is based on ASTM C1581/C1581-18a, but differs in that K13 or LC3-K13 is on a steel ring with an outer diameter of 405mm and an inner diameter of 385mm rather than inside a hollow ring as used in the restricted test Cast solid. Beginning 5 hours after casting, the K13 or LC3-K13 expansion applied pressure to the steel ring and the resulting steel ring strain was monitored by 3 strain gauges.

Figure 5 plots the average strain for 3 strain gauges. Similar to the dry expansion described in Section 3.1, the restricted expansion also increases initially and then decreases. As shown in Figures 1 and 2, the maximum dry expansion occurred between 2 and 3 days. However, due to creep and relaxation, the maximum restricted expansion occurs about the first day after casting. The maximum expansion of K13 was 123 με and the maximum expansion of LC3-K13 was 104 με, then the maximum expansion of K13 was reduced to 6 με and the maximum expansion of LC3-K13 to 56 με on day 28. LC3-K13 has less swelling reduction than K13, which indicates that LC3-K13 can provide better coupling than K13.

The residual interfacial pressure between the steel ring and K13/LC3-K13 can be calculated by equation (8):

where presidual ( t ) is the _residual interfacial pressure, εsteel ( t ) is the strain measured by 3 strain gauges, E _steel is the Young's modulus of the _steel ring, and R _{O steel} and R _{I steel} are the steel ring Outside diameter and inside diameter.

Figure 6 plots the residual interface pressure calculated by equation (8). After 1 day, the maximum pressure for K13 was 1.18 MPa and the maximum pressure for LC3-K13 was 1.00 MPa. After 28 days, the pressure of K13 was only 0.06MPa, almost 0MPa, while the pressure of LC3-K13 was 0.54MPa.

Compared to traditional restorative materials, SDMCC (K13 or LC3-K13) is designed to exert pressure on the main tube. The experimental data in this paper confirm this concept. Without wishing to be bound by theory, it is believed that the pressure improves the coupling between the main pipe and the SDMCC, thereby reducing or eliminating the problems of buckling and debonding due to poor adhesion. The inventors have unexpectedly found that, advantageously, LC3 can provide less swelling reduction over time than OPC, resulting in sustained pressure on the outer tube. Coupling can be achieved without adhesive, but by mechanical friction that increases with the normal (radial) pressure applied by the SDMCC to the main pipe.

4. Tensile properties

For tensile testing, specimens were cast into dog-bone-shaped molds (see Felekoglu, B., et al., Influence of matrix flowability, fiber mixing procedure, and curing conditions on the mechanical performance of HTPP-ECC for dog-bone geometry). Composites Part B: Engineering, 2014, 60, 359-370). Uniaxial tensile tests were performed with an Instron servo hydraulic testing machine under displacement control at a rate of 0.5 mm/min. Strain was measured by two linear variable displacements (LVDTs) with a gauge length of 80 mm. The average crack width was calculated from the number of cracks by bit removal. The tensile results listed in Table 2 are the average of 3 samples at 28 days.

FIG. 7 plots representative tensile stress and strain curves for the SDMCCs in Table 1. FIG. The ultimate tensile strength and tensile strain capacity of OPC are 3.41MPa and 3.69%. For SDMCC mixed with CSA-K, the ultimate tensile strengths of K07, K10 and K13 were 3.67 MPa, 3.62 MPa and 3.85 MPa, respectively. Including CSA-K increases ultimate tensile strength. The tensile strain capacities of K07, K10 and K13 are 4.79%, 5.17% and 5.04%, respectively, each of which is greater than the tensile strain capacity of OPC. When the strains were 1%, 2% and 3%, the average crack widths were about 60 μm, 80 μm and 90 μm. Cracks in SDMCC prepared with CSA-K The width is smaller than the crack width of SDMCC prepared with OPC. The tensile strain capacity and crack width of LC3-K10 and LC3-K13 are comparable to SDMCC prepared with OPC. However, the ultimate tensile strength is below 3 MPa. While LC3 yields lower strength, SDMCC prepared with LC3 has greater strain capacity and uses less cement. Advantageously, these SDMCCs may have good durability, lower cost, and be more environmentally friendly than SDMCCs prepared with OPC. The durability and permeability of SDMCC are discussed further below.

Even though the SDMCC may experience microfracture damage under external loading, the material can still undergo self-healing, which can be enhanced under the wet-dry environmental conditions that typically exist inside pipelines. After curing for 28 days, the specimens were pre-ruptured to 1% and 2% strain to intentionally damage the SDMCC. Subsequently, the samples were exposed to seven wet-dry cycles. Figure 8 plots strength and strain capacity results after self-healing. Although the samples were pre-broken, the tensile strengths of the samples after self-recovery were higher than those of the original samples. SDMCC prepared with LC3 cement showed higher strain capacity than SDMCC prepared with OPC, which indicates that SDMCC prepared with LC3 has comparable or even better self-healing performance.

After curing for 28 days, the specimens were pre-cracked to 1% and 2% strain, followed by Liu, H., et al., " Influence of micro-cracking on the permeability of Engineered Cementitious Composites ", Cement and Concrete Composites, 2016 , 72, 104-113 in the procedure for penetration testing. Figure 10 presents the permeability coefficient results after 14 days. As expected, the permeability coefficient increases with fracture width. The permeability of SDMCC (LC3-K13) is lower than that of SDMCC (OPC) due to its tight fracture width pattern. The permeability coefficient of SDMCC is almost two orders of magnitude smaller than conventional reinforced mortars (>150 μm crack width) subjected to the same pre-fracture strain. The low permeability of this SDMCC should significantly improve the life performance of the pipeline and prevent leakage. Even at 2% pre-rupture strain, low permeability is expected to reduce the risk of potable water loss or subsurface water contamination, for example, following a seismic event.

5. Pipe Dressing Test

To demonstrate the trimming capability of the SDMCC, a pipe crush test was performed according to ASTM C497M-19a. Figure 10 shows pipeline sections before and after repair with SDMCC (LC3-K13). As shown in Figure 10 The SDMCC repair layer thickness shown is only an example. Those skilled in the art will understand that the actual SDMCC thickness can be selected depending on the mechanical and functional requirements of a particular application. The pipe length is 36" (914mm). The original concrete pipe was mixed with 500g/L OPC, 1200g/L river sand, 200g/L water and 6g/L water reducer. The SDMCC mixture was the same as LC3-K13 in Table 1. In Seven days after the concrete was cast, the concrete and kraft paper tubes were placed in a water tank. The kraft paper tubes were demolded after 3 hours of immersion in water, after which SDMCC (LC3-K13) was cast.

After curing in air for 28 days, the pipe was cut by a diamond saw to 8" (203mm) lengths for crush testing. Crush testing was performed with concrete pipe and pre-cracked pipe repaired with LC3-K13. Cracked concrete pipes to simulate the effect of repairing broken pipes using SDMCC.

When the load exceeds the crushing strength, the concrete pipe suddenly collapses due to its brittleness. However, the pre-damaged pipe repaired by SDMCC was able to carry loads after a giant crack appeared in the concrete pipe. Many microcracks appear in SDMCC. Cracks first appeared in the SDMCC inner surface, and then more cracks appeared as the load increased. Many tight cracks are distributed throughout the SDMCC instead of one giant crack in the concrete pipe.

This test also confirmed that SDMCC eliminated buckling, a common problem in pipes repaired by the CIPP method. Buckling usually occurs due to the gap between the repaired layer and the main pipe, which is usually observed in the CIPP method. The swelling properties of the SDMCC can provide a coating of the SDMCC that couples seamlessly to the main pipe, creating little or no gaps therebetween.

Figure 11 plots crushing strength versus displacement test results. Both the crushing strength and displacement capacity of the pipe repaired by LC3-K13 are greater than the crushing strength and displacement capacity of the concrete pipe. This situation shows that trimming the pipe with SDMCC improves both the strength and displacement capacity of the pipe (also shown in Table 4). Even after peak loads, the SDMCC retains residual load capacity. When the residual load drops to 4.89kN, which is equal to the load capacity of the original detection concrete pipe, the displacement is 3.63 times the displacement capacity of the detection concrete pipe.

Table 4

6. Leak test

Use SDMCC repaired tubes for leak testing. After reaching the peak load, the bottom portion of the ruptured SDMCC pipe was cemented on plywood. Subsequently, the system is filled with water. There was no leakage from the system 24 hours after filling with water, regardless of the giant cracks in the main concrete pipe and the microcracks in the SDMCC. Microcracks in the SDMCC extend from the inner surface to the outer tube. Without wishing to be bound by theory, it is believed that multiple tight fractures work as plastic hinges and redistribute stress. Micro-cracks do not propagate into giant cracks, and local cracks do not appear in SDMCC. Therefore, there is no leakage even after the peak load has been reached.

It is not intended to limit the scope of this creation to the examples mentioned above. Those skilled in the art will appreciate that many variations are possible without departing from the scope of the present invention as set forth in the scope of the appended claims.

100: Raw Concrete Pipe

8”牛皮紙管 102:

8" Kraft Paper Tube

6”牛皮紙管 103:

6" Kraft Paper Tube

4.5”牛皮紙管 104:

4.5" Kraft Paper Tube

105: SDMCC

Claims (28)

A spraying system comprising: a spraying body having a chamber and a nozzle connected to the chamber, and a sprayable cementitious composition contained in the chamber and suitable for spraying through the nozzle, the The sprayable cementitious composition comprises: a composite binder, fibers and water; wherein the composite binder comprises a cement component and a pozzolan component, wherein the cement component comprises a hydraulic cement and an expansion agent, and wherein the amount of the expansion agent is from about 30 wt % to about 60 wt % based on the weight of the total cement components. The spray system of claim 1, wherein the ratio of water to composite binder is from about 0.2 to about 0.5. The spray system of claim 1, wherein the expansion agent is calcium monosulfoaluminate. The spray system of claim 3, wherein the calcium sulfoaluminate is CSA-K or CSA-R. The spray system of claim 4, wherein the calcium sulfoaluminate is CSA-K. The spray system of any one of claims 1 to 5, wherein the amount of the expansion agent is from about 30 wt % to about 50 wt % based on the weight of the total cement components. The spray system of any one of claims 1 to 5, wherein the hydraulic cement comprises ordinary Portland cement. The spray system of any one of claims 1 to 5, wherein the hydraulic cement is present in an amount of from about 1 wt% to about 70 wt% based on the weight of the total cement components. The spray system of any one of claims 1 to 5, wherein the cement component comprises a reactive aluminosilicate, a calcium carbonate, or a mixture thereof. The spray system of claim 9, wherein the reactive aluminosilicate is a calcined clay. The spray system of claim 9, wherein the calcium carbonate is a limestone. The spray system of any one of claims 1 to 5, wherein the amount of the buzuolan component is about 1 to about 3 times the amount of the cement component by weight. The spray system of any one of claims 1 to 5, wherein the amount of the buzuolan component is about 2 times to about 2.5 times the amount of the cement component by weight. The spraying system of any one of claims 1 to 5, wherein the buzuolan component comprises a material selected from the group consisting of fly ash, steel slag, granular blast furnace slag, diatomaceous earth, Silica fume; calcined clays, such as metakaolin; calcined phyllolites, pozzolans, pumice; calcined silica-rich organic matter, such as rice husk ash; and mixtures of any two or more thereof. The spray system of claim 14, wherein the fly ash is selected from the group consisting of Type C fly ash, Type F fly ash, and mixtures thereof. The spray system of any one of claims 1 to 5, wherein the fibers are selected from the group consisting of polymeric fibers, inorganic fibers, metal fibers, carbon fibers, plant-based fibers, and any two thereof or a mixture of more. The spray system of claim 14, wherein the polymer fibers comprise a polymer material selected from the group consisting of: a polyolefin, a polyacrylic acid, a polyester, a polyvinyl alcohol, a polyamide and any combination of two or more thereof. The spray system of claim 16, wherein the polymer fibers are selected from the group consisting of polyethylene fibers, high tenacity polypropylene fibers, polyvinyl alcohol fibers, and mixtures of any two or more thereof. The spray system of any one of claims 1 to 5, wherein the sprayable cementitious composition further comprises one or more components selected from the group consisting of: a superplasticizer, an aggregate, a Adhesive and a retarder. A spray system comprising: a spray body having a chamber and a nozzle connected to the chamber, and a sprayable cement contained in the chamber and adapted to be sprayed through the nozzle The sprayable cementitious composition comprises: a composite adhesive, fibers and water; wherein the composite adhesive comprises a cement component and a pozzolanic component, and wherein the sprayable cementitious composition The material when cured achieves one or more properties selected from the group consisting of (i) a tensile strength of at least about 2.50 MPa, (ii) a tensile strain capacity of at least about 3% at 28 days , (iii) a fracture width of less than about 100 μm at ε < 2%, and (iv) a maximum expansion of at least about 1210 με; wherein the cement component comprises a hydraulic cement and a swelling agent, and wherein based on the total cement The bulking agent is present in an amount of about 30 wt % to about 60 wt %, based on the weight of the components. A spraying system comprising: a spraying body having a chamber and a nozzle connected to the chamber, and a sprayable cementitious composition contained in the chamber and suitable for spraying through the nozzle, the The sprayable cementitious composition comprises: a composite binder, fibers and water; wherein the composite binder comprises a cement component and a buzuolan component, and wherein the cement component comprises a hydraulic cement and an expansive agent, and wherein: a) the hydraulic cement comprises i. ordinary portland cement in an amount of from about 10 wt % to about 25 wt %, based on the weight of the total cement components, ii. based on the weight of the total cement components, Metakaolin in an amount of about 30%, and iii. limestone in an amount of about 15% based on the weight of the total cement components; b) the swelling agent is calcium monosulfoaluminate, based on the weight of the total cement components In total, in an amount of about 30 wt % to about 45 wt %; c) the buzuolan component comprises fly ash in an amount of about 30 wt % to about 45 wt % based on the weight of the total cement component. A restored and/or refurbished building structure comprising a building structure and a A repair layer made of a sprayable cementitious composition contained in a spray system as claimed in any one of claims 1 to 21 and disposed on a surface of the building structure. The repaired and/or finished building structure of claim 22, wherein the repair layer is sprayed on the surface of the building structure by using a manual spraying system or an automated spraying system, the sprayable cementitious composition formed above. The restored and/or reconditioned building structure of claim 22, wherein the building structure is a pipeline. The restored and/or reconditioned building structure of claim 24, wherein the surface is the inner surface of the pipeline. The repaired and/or finished building structure of claim 25, wherein the cementitious composition exerts an expansion force on the inner surface of the pipeline. The repaired and/or reconditioned building structure of claim 26, wherein the cementitious composition is coupled to the inner surface of the pipeline. The restored and/or reconditioned building structure of any one of claims 24 to 27, wherein the pipeline is reconditioned to extend the life of the pipeline, increase the bearing capacity of the pipeline, and/or strengthen the pipeline.

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