Prefabricated rectangular columnar member of multilayer cementitious composition

Abstract

The present invention relates to a multi-layer composite member including a cementitious layer that expands upon hardening. The composite member includes an inner layer including a first cementitious material and an outer layer, the inner layer substantially covering the inner surface of the outer layer, the first cementitious material being an expandable material that exerts a force on the inner surface of the outer layer. The present invention also relates to the manufacture of the composite member and to the use of the composite member, for example as a pipeline or building member.

Description

[Technical Field]

[0001] The present invention relates to a multi-layer composite member comprising a cementitious layer that expands on hardening, and also to the production of such a composite member and its use, for example as a pipeline or building member. [Background technology]

[0002]

[0002] Pipelines are critical infrastructure and can be used to transport and distribute useful commodities such as oil, gas, and water. Pipelines used for these purposes are often subjected to severe mechanical and environmental stresses. As a result, both metal and concrete pipes are prone to problems such as cracking, spalling, and debris accumulation. Metal pipes can corrode or deform.

[0003]

[0003] In a variety of applications where pipeline infrastructure is utilized, pipeline failures can result in significant costs, environmental damage, and / or safety issues. Drinking water leaks are a well-known problem, with major cities such as Boston losing approximately 70 million gallons of drinking water daily since the late 1970s. Leaks from underground sewer systems can result in contamination of aquifers. Leaks from gas lines have been known to cause large-scale fires.

[0004]

[0004] One option for addressing pipeline infrastructure failures is the repair or upgrade of existing pipelines using sprayed cement-based materials. WO 2021 / 167635 A1 describes a method for the repair and upgrade of existing pipelines using fiber-reinforced toughened cementitious composites (ECC). The method described in WO 2021 / 167635 A1 can be used, for example, to provide a repaired or upgraded pipeline that has a higher load and deflection capacity than the original pipeline, and therefore reduces failure events in the pipeline.

[0005] However, in some cases it would be beneficial to provide a prefabricated pipeline having improved properties that allow it to withstand higher internal and / or external loads than conventional pipelines.

[0006]

[0006] One object of the present invention is to go some way toward fulfilling this desire and / or at least to provide the public with a useful choice.

[0007] Further objects of the present invention will become apparent from the following description, which is given by way of example only.

[0008] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention and is not to be construed as an admission that any or all of such matters form part of the prior art or were common general knowledge in the art relevant to the present invention as they existed prior to the priority date. Summary of the Invention

[0009] In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: an inner layer comprising a first cementitious material; an outer layer, wherein the inner layer substantially covers an inner surface of the outer layer, and the first cementitious material is an expansive material that exerts a force on the inner surface of the outer layer.

[0010] In a second aspect, the present invention provides a method for producing a composite member according to the first aspect, comprising: - spraying an unhardened mixture of a first cementitious material onto the inner surface of the outer layer; - hardening the first cementitious material to obtain a composite member; The present invention provides a method comprising:

[0011] In a third aspect, the present invention provides a method for manufacturing a composite member comprising an inner layer comprising a first cementitious material that expands upon hardening, a formwork layer, and an outer layer, the inner layer contacting an outer surface of the formwork layer and an inner surface of the outer layer, - providing a formwork layer and an outer layer with an air gap between the two layers; - injecting a green mixture of a first cementitious material into the gap between the formwork layer and the outer layer; - hardening the first cementitious material to obtain a composite member; The present invention provides a method comprising:

[0012] In a fourth aspect, the present invention provides a composite member made according to the second or third aspect.

[0013] In some embodiments, the first cementitious material has a maximum expansion of at least about 1200 με. In some other embodiments, the first cementitious material exhibits a maximum expansion of at least about 3000 με, about 3375 με, about 4000 με, or about 4450 με.

[0014] In some embodiments, the outer layer comprises a second cementitious material. In some embodiments, the second cementitious material shrinks upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of less than about 500 μm. In some embodiments, the second cementitious material exhibits shrinkage of about 50 to about 500 μm upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of about 100 to about 400 μm upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, or about 400 μm upon hardening.

[0015] In some embodiments, the second cementitious material exhibits shrinkage of less than about 1000 με upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of less than about 500 με upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of about 50 to about 500 με upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of about 100 to about 400 με upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of about 50 με, about 100 με, about 150 με, about 200 με, about 250 με, about 300 με, about 350 με, or about 400 με upon hardening. In some embodiments, the second cementitious material exhibits shrinkage of about 300 to about 350 με upon hardening.

[0016] In some embodiments, the first cementitious material and / or the second cementitious material comprises a composite binder. In some embodiments, the composite binder comprises a cement component and a pozzolanic component. In some embodiments, the cement component comprises a hydraulic cement.

[0017] In some embodiments, the first cementitious material and / or the second cementitious material comprises fibers.

[0018] In some embodiments, the first cementitious material and / or the second cementitious material comprises a fiber reinforced toughened cementitious composite material.

[0019] In some embodiments, the first cementitious material and / or the second cementitious material are sprayable.

[0020] In some embodiments, the cement component of the first cementitious material comprises an expanding agent. In some embodiments, the expanding agent is calcium sulfoaluminate.

[0021] In some embodiments, the inner layer covers substantially all of the inner surface of the outer layer. In some embodiments, the outer layer covers substantially all of the outer surface of the inner layer.

[0022] In some embodiments, the outer layer comprises a metal, a polymer, a composite material, or a combination of any two or more thereof. In some embodiments, the metal is steel. In some embodiments, the polymer is polyvinyl chloride (PVC). In some embodiments, the composite material is a fiber-reinforced plastic.

[0023] In some embodiments, the form layer comprises a metal, a polymer, a composite material, or a combination of any two or more thereof.

[0024]

[0024] In some embodiments, the composite member is prefabricated.

[0025] In some embodiments, the composite member is hollow. In some embodiments, the composite member is solid. In some embodiments, the composite member is in the shape of a tube, a column, or a slab. In some embodiments, the cross section of the composite member is circular, oval, square, rectangular, pentagonal, hexagonal, heptagonal, or octagonal.

[0026] In a further aspect, the present invention provides the use of a composite member of the first or fourth aspect as a tube, the composite member being hollow.

[0027] In some embodiments, the cross section of the composite member is circular.

[0028]

[0028] In some embodiments, the pipe is for transporting water, gas, or oil.

[0029] In a further aspect, the present invention provides the use of a composite member of the first or fourth aspect as a building member.

[0030]

[0030] In some embodiments, the building component is a column or a slab.

[0031]

[0031] The invention may be broadly said to consist in the parts, elements, and features referred to or shown in this specification of the present application, individually or collectively, and any and all combinations of any two or more of said parts, elements, or features, and where a particular whole that has a known equivalent in the art to which the invention pertains is referred to in this specification, such known equivalent is deemed to be incorporated herein as if set forth individually.

[0032]

[0032] Furthermore, those skilled in the art will recognize that when features or aspects of the invention are described in terms of a Markush group, the invention is also thereby described in terms of every individual element or subgroup of elements of that Markush group.

[0033]

[0033] As used herein, "(s)" after a noun refers to the plural and / or singular form of that noun.

[0034] As used herein, the term "and / or" means "and" or "or" or both.

[0035]

[0035] As used herein, the term "comprising" means "consisting at least in part of." When interpreting each expression in this specification that includes the term "comprising," features other than those preceded by this term may be present. Related terms such as "comprise" and "comprises" should also be interpreted in the same way.

[0036] Reference to a range of numbers disclosed herein (e.g., 1 to 10) is intended to include reference to every rational number within that range (e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10), and to every range of every rational number within that range (e.g., 2 to 8, 1.5 to 5.5, and 3.1 to 4.7); thus, every subrange of every range expressly disclosed herein is expressly disclosed herein. These are merely examples of what is specifically intended, and every possible combination of numerical values ​​between the minimum and maximum values ​​recited should be considered to be expressly set forth in this application in a similar manner.

[0037]

[0037] While the present invention is broadly defined as above, those skilled in the art will recognize that the present invention is not limited thereto and that the present invention also includes embodiments of which examples are illustrated by the following description. [Brief explanation of the drawings]

[0038]

[0038] The present invention will now be described with reference to the drawings.

[0039] [Figure 1] A two-ply composite member is shown. [Figure 2]

[0040] A three-layer composite member is shown. [Figure 3]

[0041] 1 illustrates different geometries of three-ply composite members, specifically (a) hollow composite member with a square cross section, (b) hollow composite member with a hexagonal cross section, (c) solid composite member with a circular cross section, and (d) solid composite member with a rectangular cross section. [Figure 4]

[0042] 1 shows a configuration of a form layer and an outer layer that can be used to cast a three-layer composite member. [Figure 5]

[0043] Figure 1 shows the shrinkage / expansion of sprayable ductile metal-like cementitious compositions (SDMCC) prepared with OPC and CSA-K cements (where CSA-K contains 7, 10, and 13 wt. % composite binder, respectively). [Figure 6]

[0044] Figure 1 shows the shrinkage / expansion of SDMCC prepared with OPC and LC3 / CSA-K cements (where CSA-K contains 10 and 13 wt % composite binder, respectively). [Figure 7]

[0045] 1 shows the shrinkage / expansion of SDMCC prepared with CSA-R cement (where the anhydrite contains 0, 10, 15, and 20 wt. % CSA-R, respectively). DETAILED DESCRIPTION OF THE INVENTION

[0040]

[0046] The present disclosure relates to multi-layer composite members having advantageous properties, for example, the ability to withstand internal and external loads, and being useful in a variety of applications, such as pipelines or building components (e.g., columns or slabs).

[0041]

[0047] The composite member includes two or more layers, including an outer layer and an inner layer in contact with the inner surface of the outer layer. The inner layer includes a first cementitious material that expands upon hardening. Advantageously, the expansion force of the first cementitious material forms a mechanical bond (friction bond) between the inner and outer layers. A further potential advantage of the mechanical bond is that no adhesives or mechanical fasteners (e.g., fasteners or screws) are required to achieve the bond between the layers. The bond and composite nature of the two or more layers can result in a composite member with improved properties, such as the ability to withstand structural loads, over a monolithic layer of the same cross-sectional size and shape.

[0042]

[0048] The outer layer can include a second cementitious material. In some embodiments, the second cementitious material shrinks upon hardening. Advantageously, the second cementitious material shrinking upon hardening can exert a force against the outer surface of the inner layer, resulting in a compacting / bonding effect. Alternatively, the outer layer can include a conventional building material, such as, but not limited to, a metal (e.g., steel), a polymer (e.g., PVC), a composite (e.g., fiber-reinforced plastic), or a combination of two or more thereof. Advantageously, the combination of an inner layer including a first cementitious material and an outer layer including a conventional building material can provide improved properties over the conventional building material alone. For example, a composite member including a first cementitious material layer and a metal layer can provide corrosion protection compared to, for example, a metal layer alone (e.g., a steel pipe). A composite member can also provide increased stiffness compared to, for example, a PVC layer alone (e.g., a PVC pipe).

[0043]

[0049] The first cementitious material is a cementitious material that expands upon hardening. The first cementitious material can have a maximum expansion of at least about 1200 με, e.g., at least about 3000 με, about 3375 με, about 4000 με, or about 4450 με. Those skilled in the art will recognize that any suitable conventional cementitious material having suitable expansion characteristics can be useful in the composite member. For example, the first cementitious material can include a hydraulic cement and an expanding agent. In some embodiments, the expanding agent is calcium sulfoaluminate. Preferably, the first cementitious material is a sprayable ductile metal-like cementitious composition (SDMCC) as described in WO 2021 / 167635 A1.

[0044]

[0050] Those skilled in the art will recognize that the first and second cementitious materials can be prepared from conventional cementitious materials, provided that the required expansion and contraction characteristics are obtained. For example, the first and / or second cementitious materials can be fiber-reinforced composite materials, such as an enhanced concrete cementitious composite (ECC). Exemplary formulations for cementitious materials are described in more detail below.

[0045]

[0051] The exact shape, size, and number of layers, as well as the materials, can be selected to suit the performance requirements of the composite member application.

[0046]

[0052] A composite member includes at least two layers, having an inner layer (1) and an outer layer (2), as shown in Figure 1. However, a composite member can include other layer combinations depending on the intended use and desired properties of the composite. For example, a composite member can include three layers, as shown in Figure 2, having an inner layer (10), an outer layer (12), and a coating layer (14) that includes a second cementitious material that shrinks upon hardening.

[0047]

[0053] In some embodiments, the composite member can include an additional inner layer. The additional inner layer can be useful, for example, as a permanent mold layer for casting the inner layer. In some embodiments, the inner layer contacts the outer surface of the mold layer and the inner surface of the outer layer. The mold layer can include, for example, a material that can receive tension from the expandable inner layer. Those skilled in the art are familiar with molds and can select an appropriate material for the mold layer. Suitable materials for the mold layer include, but are not limited to, metal (e.g., steel), polymer (e.g., PVC), composite material (e.g., fiber-reinforced plastic), or a combination of two or more thereof.

[0048]

[0054] The cross section of the composite member can be circular, rectangular, or any other shape. In some applications, the composite member is hollow, as shown, for example, in Figures 1, 2, 3(a), and 3(b). Figure 3(a) shows a composite member with a square cross section including an inner layer (30) comprising a first cementitious material, an outer layer (32), and a coating layer (34) comprising a second cementitious material. Figure 3(b) shows a composite member with a hexagonal cross section including an inner layer (40) comprising a first cementitious material, an outer layer (42), and a coating layer (44) comprising a second cementitious material. Such applications include applications in pipelines, such as civil or industrial pipeline infrastructure for transporting drinking water or wastewater, or pipelines for other fluids such as gas or oil. In some applications, the composite member is solid. For example, the composite member can be provided as a solid column or slab, as shown in Figures 3(c) and 3(d), which are useful as building components. Figure 3(c) shows a composite member having a circular cross-section including an inner layer (50) comprising a first cementitious material, an outer layer (52), and a coating layer (54) comprising a second cementitious material. Figure 3(d) shows a composite member having a rectangular cross-section including an inner layer (60) comprising a first cementitious material, an outer layer (62), and a coating layer (64) comprising a second cementitious material. While the composite members in Figures 2 and 3 are shown as including an inner layer, an outer layer, and a coating layer, these three-layer composite members can also be provided with other layer combinations. For example, the composite member shown in Figure 2 can include a formwork layer (10), an inner layer (12), and an outer layer (14). Therefore, those skilled in the art will recognize that the shape, size, and number of layers, as well as the materials, of a composite member can be selected depending on the intended application.

[0049] hydraulic cement

[0055] 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 of these are also contemplated. Preferably, the hydraulic cement is Portland cement.

[0050]

[0056] Portland cement is a finely ground powder produced by grinding clinker, which consists essentially of hydraulic calcium silicate. This cement can contain up to about 5% gypsum. The amount of gypsum present affects the setting time. Portland cement specifications are set forth in ASTM C 150, Standard Specification for Portland Cement, which defines eight types of Portland cement: Type I, Type IA, Type II, Type IIA, Type III, Type IIIA, Type IV, and Type V. Type I cement is a general-purpose ordinary Portland cement (OPC) suitable for any use where the specialized properties of another type are not required. Type III cement is chemically and physically similar to Type I cement, except that it is more finely ground to achieve higher early strength.

[0051]

[0057] The cement component of the cement-based material can include hydraulic cement in an amount of about 1 to about 80 wt%, about 20 to about 80 wt%, about 50 to about 80 wt%, or about 60 to about 80 wt%, based on the weight of the total cement component.

[0052]

[0058] In some embodiments, the cement component comprises a reactive aluminosilicate, such as calcined clay, and / or calcium carbonate, such as limestone. Advantageously, replacing a portion of the hydraulic cement with a reactive aluminosilicate and / or calcium carbonate results in a more environmentally friendly composition by reducing the amount of carbon released during the manufacturing process.

[0053]

[0059] Cementitious materials containing reactive aluminosilicates and / or calcium carbonate may exhibit additional advantages. For example, limestone-burnt clay cement (LC3) pastes have been found to have finer pore structures than pastes made from OPC. Advantageously, the pore densification provides excellent resistance to chloride penetration and good performance in the presence of sulfates, which is particularly important in the complex environments found in pipelines.

[0054]

[0060] Furthermore, cementitious materials containing LC3 have surprisingly been found to have higher strain capacity and smaller crack widths than prior art ECC made with OPC. The reduced crack width reduces permeability. Cementitious materials with higher strain capacity are expected to have greater deformability. This can result in composite members with, for example, higher load and deflection capacities.

[0055]

[0061] The cement component can include reactive aluminosilicate, calcium carbonate, or a mixture thereof in an amount of about 1 to about 80 wt%, about 30 to about 60 wt%, or about 40 to 50 wt%, based on the total cement component weight. For example, the cement component can include reactive aluminosilicate in an amount of about 0 to about 50 wt%, about 20 to about 40 wt%, or about 30 wt%, based on the total cement component weight. For example, the cement component can include calcium carbonate in an amount of about 0 to about 30 wt%, about 10 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.

[0056]

[0062] 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, and in some embodiments, the average particle size of the calcium carbonate is from about 2 μm to about 100 μm, or from about 2 μm to about 20 μm.

[0057]

[0063] In some embodiments, the cement component comprises about 10 to about 50 wt. % OPC, about 20 to about 40 wt. % metakaolin, and about 10 to about 20 wt. % limestone, based on the total cement mixture weight.

[0058]

[0064] In some embodiments, a portion of the hydraulic cement can be replaced with mining tailings. For example, the cement component can include mining tailings in an amount of about 1 to about 30 weight percent, based on the weight of the total cement component.

[0059] leavening agent

[0065] An expanding agent is a material that increases the expansion of a cementitious material during the hydration process. In some embodiments, the expanding agent can be used to reduce shrinkage that occurs during the hardening of the composition. For example, the expanding agent can be used to reduce the inherent shrinkage characteristics of the cementitious material to obtain a suitable cementitious material for the outer layer (i.e., the second cementitious material). In another embodiment, the expanding agent can be used to obtain a cementitious material that expands during hardening. Advantageously, increased expansion of the cementitious material can reduce the risk of cracking that occurs during shrinkage.

[0060]

[0066] The expansion agent can be used to adjust the expansion properties of the first cementitious material, such that when applied to the inner surface of the outer layer and cured, the cementitious material exerts an expansion force on the outer layer. The expansion force reduces any space between the cementitious material and the outer layer, increasing mechanical friction therebetween. Advantageously, the increased mechanical friction can increase the adhesive strength between the cementitious material and the outer layer. As a result, the composite member can have a higher load and deflection capacity than a monolithic member. Furthermore, the increased adhesive strength can reduce delamination of the cementitious material from the outer layer, as well as wrinkling and even buckling of the composite member. However, those skilled in the art will recognize that in some embodiments, excessive expansion should be avoided because it can result in deformation of the outer layer. Therefore, the amount of desired expansion force is determined in part by the material properties of the outer layer.

[0061]

[0067] Preferred expanding agents include calcium aluminate cement (CAC) and calcium sulfoaluminate cement (CSA). Preferably, the expanding agent is CSA. The amount of CaSO·nH2O in the CSA is preferably about 1 to 50 wt % based on the weight of the CSA, where n can be 0, 0.5, 1, or 2.

[0062]

[0068] The first cementitious material can include an expanding agent in an amount of about 10 to about 60 weight percent, or about 20 to about 50 weight percent, based on the weight of the total cement component. In some embodiments, the expanding agent has an average particle size of about 2 μm to about 500 μm, or about 10 μm to about 30 μm.

[0063] Pozzolana

[0069] Pozzolans are silica-containing or silica-aluminum-containing materials, typically provided in finely divided form. While pozzolans alone exhibit little or no cementitious properties, in the presence of water, they react with calcium hydroxide released by the hydration of hydraulic cement to form calcium silicate hydrate and other cementitious compounds. Advantageously, pozzolans can improve the fracture toughness of the binder of cementitious materials, thereby increasing the ductility of the hardened cementitious material. Pozzolans can also be used to modify the rheology of cementitious materials. Advantageously, the rheology of the cementitious material can be modified to improve the pumpability and / or sprayability of the composition.

[0064]

[0070] Generally, any silica-containing or silica-aluminum-containing material that reacts with calcium hydroxide in the presence of water may be suitable for use in the binder. Examples of suitable pozzolans include, but are not limited to, fly ash, steel slag, granulated blast furnace slag, diatomaceous earth, silica fume, calcined clays such as metakaolin, calcined shale, volcanic ash, pumice, calcined silica-rich organic matter such as rice husk ash, and mixtures of any two or more thereof. Preferably, the pozzolanic component comprises fly ash, for example, as defined in ASTM C618. In some embodiments, the fly ash is Type C fly ash and / or Type F fly ash.

[0065]

[0071] In some embodiments, the pozzolanic component comprises silica fume. Advantageously, silica fume can increase the compressive strength of the cementitious material and / or improve fiber / matrix interfacial bonding in embodiments where the first cementitious material comprises fibers.

[0066]

[0072] The composite binder can include the pozzolan component in an amount from about 0 to about 3 times the weight of the cement component. Preferably, the composite binder includes the pozzolan component in an amount from about 1 to about 3 times, more preferably from about 2 to about 3 times, and more preferably from about 2 to about 2.5 times the weight of the cement component.

[0067] fiber

[0073] Fibers are intended to reinforce hardened cementitious materials. Suitable fibers can be selected based on various properties, such as the desired cost, mechanical properties, physical properties, and bonding characteristics of the fibers. The properties of cementitious materials can be influenced by factors such as fiber length, diameter, chemical composition, stiffness, density, and strength. Fibers can be selected to transfer loads across cracks when the composite is loaded beyond the elastic stage. These load transfer behaviors can be adjusted to balance fiber fracture and fiber slippage, i.e., controlled fiber bridging behavior. Excessive fiber fracture or fiber slippage during load application on a composite is undesirable because it can limit the ductility of the composite or result in excessively large crack widths that compromise the durability of the composite. Advantageously, fibers can improve strain hardening and tensile strength of the composite member and limit crack widths.

[0068]

[0074] Fibers suitable for use in cementitious materials include, but are not limited to, polymeric fibers, inorganic fibers (e.g., basalt and glass fibers), metal fibers (e.g., steel fibers), carbon fibers, plant fibers (e.g., cellulose and lignocellulosic fibers), and mixtures of any two or more thereof. Preferably, the fibers are polymeric fibers, i.e., fibers composed of a polymeric material such as polyolefin (e.g., polyethylene or polypropylene), polyacrylic, polyester, polyvinyl alcohol, polyamide (e.g., nylon), or a combination of any two or more thereof. More preferably, the fibers are polypropylene fibers, more preferably high tenacity polypropylene fibers. In some embodiments, the fibers are discontinuous staple fibers.

[0069]

[0075] The upper limit of fiber density is determined by pumpability and sprayability requirements, while the lower limit is determined by the ability to obtain strain-hardening (ductile) behavior as opposed to brittle or pseudo-brittle behavior. For example, the fibers can be present in an amount of about 0.1 to less than 4 v / v%, about 1 to about 3 v / v%, or about 1.5 to about 2.3 v / v%, based on the total composition volume (i.e., the volume of the composition including water). In some embodiments, the fiber length is about 4 mm to about 25 mm, about 6 mm to about 20 mm, or about 8 mm to about 12 mm. In some embodiments, the fiber diameter is about 10 μm to about 150 μm, or about 10 μm to about 60 μm.

[0070] Superplasticizer

[0076] In some embodiments, the cementitious material further comprises a superplasticizer, also known as a superplasticizer. Superplasticizers can be added to cementitious materials to affect the rheology of the composition. Advantageously, superplasticizers can reduce the amount of water required to maintain the pumpability and sprayability of the cementitious material.

[0071]

[0077] Thus, the superplasticizer is typically added to the cementitious material in an amount effective to achieve a composition with desired pumpability and sprayability. One skilled in the art will recognize that the amount of superplasticizer needed to achieve the desired pumpability and sprayability can be determined by other components of the composition, such as the water content of the composition. For example, the superplasticizer can be included in the cementitious material in an amount of about 0.1 to 10 wt. %, about 0.3 to about 3 wt. %, or about 0.5 to about 1.5 wt. %, based on the total composition weight.

[0072]

[0078] Generally, any superplasticizer known in the art would be suitable for use in cementitious materials, including, but not limited to, sulfonated melamine (e.g., sulfonated melamine formaldehyde condensates), sulfonated naphthalene (e.g., sulfonated naphthalene formaldehyde condensates), polycarboxylic acid ethers (e.g., ADVA® 190), modified lignosulfonates, and mixtures of any two or more thereof.

[0073] aggregate

[0079] The cementitious material may further include aggregates such as sand, crushed stone, and lightweight aggregate. The incorporation of lightweight aggregate can reduce the density of the cementitious material. The incorporation of lightweight aggregate can also increase the sprayed thickness, especially on horizontal overhead surfaces. When the amount of lightweight aggregate is high, the grading becomes important, otherwise strain hardening cannot be achieved. Generally, the average grading is about 10 μm to about 1000 μm, or about 10 μm to about 200 μm, or about 30 μm to about 100 μm.

[0074]

[0080] Lightweight aggregates can include, but are not limited to, ground rubber (e.g., from scrap tires), hollow glass spheres, cenospheres, expanded mica, and microballoons (e.g., glass, ceramic, or polymeric microballoons).

[0075]

[0081] In addition to, or instead of, lightweight aggregate, the cementitious material can further include gas bubbles. Gas can be introduced during processing of the cementitious composition by physical means, such as frothing or aeration. Alternatively, gas can be introduced chemically, such as hydrogen gas produced by the reaction of aluminum powder with an alkaline composition or Si-H functional silane with water. In some embodiments, a stabilizing agent is added to help prevent adjacent gas bubbles from coalescing. In some embodiments, the gas can have a saturation of about 1400 kg / m. 3 or more, preferably 1500 kg / m 3The volume percent is limited to achieve a hardened density of 1300 kg / m or greater. If large voids are formed due to numerous coalescence, the strength properties of the composite, especially the strain hardening behavior, may be compromised. Air bubbles can be used in conjunction with other lightweight aggregates. Advantageously, the volume percent of air bubbles in such mixes can be kept small to minimize coalescence. For example, if the target density is 1300 kg / m, the strength properties of the composite, especially the strain hardening behavior, may be compromised. 3 For composite materials, the strength is approximately 1600 kg / m 3 Gases or gas precursors can be added to achieve higher densities, and other lightweight fillers can be added to reduce the density to the target range.

[0076] Other additives

[0082] The cementitious material may further include other additives known in the art, such as viscosity agents and / or retarders.

[0077]

[0083] For example, the viscosity agent may be a cellulose derivative such as hydroxypropyl methylcellulose (HPMC). The viscosity agent may be added to the cementitious material in an amount of about 0 to about 1 wt. %, or about 0.03 to about 0.5 wt. %, or about 0.05 to about 0.2 wt. %, based on the total binder weight (i.e., the weight of the composition excluding water). The viscosity agent improves the composite's ability to increase thickness on the substrate and also promotes uniform fiber dispersion in the matrix.

[0078]

[0084] The cementitious material may include a retarder. Conventional retarders may be used. A preferred retarder is citric acid, which is advantageously compatible with the use of CSA. The retarder may be included in an amount of about 0.01 to about 10 wt. %, or about 0.1 to about 2 wt. %, or about 0.2 to about 1.5 wt. %, based on the total binder weight. The retarder may increase the working time of the cementitious material during the spraying process. However, those skilled in the art will recognize that excessive retarder may reduce the strength and ductility of the cementitious material.

[0079] water

[0085] The amount of water in the cementitious material affects various properties of the composition. In some embodiments, the water content should be sufficient to obtain a pumpable, sprayable composition. Generally, a higher water content reduces viscosity and improves sprayability, while a lower water content increases cohesion and allows for thicker applications. The amount of water required to obtain a pumpable, sprayable composition can be readily determined by routine experimentation and can be reduced by including a superplasticizer, as described above.

[0080]

[0086] 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, and more preferably about 0.3.

[0081] Preparation of cement-based materials

[0087] The cementitious materials of the present invention can be prepared by conventional techniques. Components can be mixed separately with water, or certain components can be premixed. In some embodiments, water is added to a premix of dry binder components to provide a wet mix, to which fibers are added. In some embodiments, a superplasticizer is mixed with water to form a solution, which is added to a premix of dry binder components to provide a wet mix, to which fibers are added. In some other embodiments, the dry components can be provided in a "ready-mix" composition, such as a premix of dry binder components and fibers, which is mixed with water and then used to form the cementitious material.

[0082] Fabrication of composite members

[0088] The composite member can be made by spraying a first cementitious material onto the inner surface of the outer layer. The first cementitious material hardens to form the inner layer, resulting in the composite member. Advantageously, if the first cementitious material is SDMCC, the hardening process is exothermic, and no heat is required to initiate the hydration and pozzolanic chemical reactions for hardening. In this process, the outer layer acts as a permanent formwork. If the composite includes a coating layer, a second cementitious material is sprayed onto the outer surface of the outer layer and hardens to form the coating layer. The first and second cementitious materials can be sprayed simultaneously or sequentially in any order onto the inner and outer surfaces of the outer layer, respectively.

[0083]

[0089] Alternatively, the composite member can be made by a casting process. For example, as shown in Figure 4, an outer layer (74) and a formwork layer (76) can be provided with a void (78) between the two layers. A first cementitious material can be poured into the void (78) and allowed to harden to yield the composite member. In some embodiments, the process can further include spraying a second cementitious material onto the outer layer and allowing the cementitious material to harden.

[0084]

[0090] The following non-limiting examples are provided to illustrate the present invention and are not intended to limit the scope of the invention in any way. [Example]

[0085] Example 1. Material composition and processing

[0091] Representative mixtures are listed in Table 1. The cement was Type I Portland cement (PC1) from Lafarge Cement Co., MI, USA. Two types of expansive cement were used, designated CSA-K and CSA-R, from CTS Cement Manufacturing Corp. and Royal White Cement Inc. The metakaolin (MK) was Sikacrete® M-100 from Sika Corporation, NJ, USA. The anhydrite was Terry-Alba No. 1 from USG. The limestone (LS) was Snowhite® 12-PT from Omya Canada Inc. The fly ash (FA) was Class C fly ash with a similar size distribution of 10-100 μm from Boral Material Technologies Inc. The superplasticizer (SP) was AVDA® 190 from GCP Applied Technologies. The viscosity agent, hydroxypropyl methylcellulose (HPMC), was from Fisher Scientific. The amount of polypropylene (PP) fibers was 2% volume fraction, 12 μm diameter, 10 mm length, Young's modulus 6 GPa, and tensile strength 850 MPa, manufactured by Brasilit, Saint-Gobain, Brazil.

[0086] [Table 1]

[0087]

[0092] The names in Table 1 reflect the binder composition. OPC and LC3 refer to binders prepared using ordinary Portland cement and limestone-burned clay cement, respectively. K07, K10, and K13 indicate that the ratio of CSA-K to the binder is 7, 10, and 13 wt.%. R13-C0, 10, 15, and 20 indicate that the ratio of CSA-R and anhydrite to the binder is 13 wt.%, with the anhydrite ratio being 0, 10, 15, and 20 wt.% of the total weight of CSA-R and anhydrite. The weight percentages of PC1, MK, and LS in LC3 cement are 55%, 30%, and 15%, respectively.

[0088]

[0093] SDMCC was prepared by mixing all dry ingredients (PC1, CSA, anhydrous gypsum, MK, LS, FA, and HPMC) in a drum mixer for 10 minutes. Water was gradually added along with SP and mixed for 6 minutes. Finally, PP fiber was added and then mixed for 6 minutes.

[0089] 2.Expansion characteristics

[0094] The specimens for shrinkage / expansion measurements were cast into prismatic molds (25 × 25 × 300 mm). The specimens were removed from the molds as quickly as possible without damage and the shrinkage / expansion measurements were performed, which was designated "time zero" for deformation. For the mixtures in Table 1, the removal times from the molds were 20 hours for OPC; 10 hours for K07; 5 hours for K10, K13, and LC3-K13; 8 hours for LC3-K10; and 3 hours for R13-C0, R13-C10, R13-C15, and R13-C20. The specimens were stored in an environment of 20 ± 2 °C and 40 ± 5% relative humidity (RH). The change in specimen length was tested according to ASTM C490 / C490M-17.

[0090] 2.1 Drying shrinkage / expansion

[0095] The shrinkage / expansion versus time curves for the compositions in Table 1 are shown in Figures 5-7, where a negative sign (on the y-axis) represents shrinkage and a positive sign represents expansion. Table 2 lists the shrinkage / expansion characteristic values ​​at 28 days. For SDMCC prepared with OPC, shrinkage continued to increase to -1434 με at 28 days. Such relatively large shrinkage can lead to cracking under restrained conditions, thereby reducing durability. SDMCC using CSA-K initially exhibited expansive behavior, followed by shrinkage. The maximum expansion occurred over a period of approximately 2 days. The magnitude of the maximum expansion was 779 με, 2418 με, and 3756 με for compositions K07, K10, and K13, which varied in CSA-K ratio. However, when 7 wt.% CSA-K cement was used in the composite binder, the SDMCC still exhibited a shrinkage of -832 με at 28 days. The expansion of K10 and K13 was 1139 με and 2026 με, respectively, at 28 days. The expansion of ECCs using LC3 was slightly less than that of OPCs. The expansion was 838 με and 1722 με for LC3-K10 and LC3-K13.

[0091]

[0096] The type of CSA cement can also affect the magnitude of expansion. CSA-R is a CSA binder with less CaSO4 than CSA-K. Even when the CSA-R content was 13 wt% of the composite binder (R13-C0), R13-C0 exhibited no expansion, shrinking at 834 με at 28 days. Increasing the replacement of CSA-R with anhydrite reduced shrinkage, and R13-C20 showed an expansion of 489 με 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 influences the formation of ettringite, which is the primary expansive hydration product of CSA cement.

[0092] 2.2 Minimum expansion

[0097] Assuming a straight material, the pressure caused by expansion is: p=E1ε1-E2ε2(1) where p is the applied pressure from the expansive SDMCC; ε1 is the maximum expansion of the SDMCC; ε2 is the difference between the maximum expansion and the residual strain at 28 days; E1 is the effective modulus between time zero and the time of maximum expansion; and E2 is the effective modulus between the time of maximum expansion and 28 days. ε1 and ε2 can be tested by the drying shrinkage / expansion test according to ASTM C490 / C490M-17, and their values ​​are listed in Table 2. E1 and E2 are effective moduli affected by stress relaxation and time evolution. During the early period (before 3 days), creep is much greater than in the later period (3 to 28 days). Furthermore, even for fast-hardening SDMCC materials, the modulus is smaller in the early period.

[0093]

[0098] Assuming E1=kE2, the pressure is: f=(kε1-ε2)E2(2) It can also be expressed as: where k is defined as the coefficient of effective modulus. k is determined by the combined effect of the evolution of the material's elastic modulus and the boundary constraint conditions. Advantageously, f should be greater than 0 to ensure that the SDMCC forms a bonding effect on the outer layer or formwork layer. In other words, kε1-ε2 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 plausible to assume k=0.5.

[0094] [Table 2]

[0095]

[0099] For the blends in Table 2, the maximum swelling and swelling of OPC after 28 days are different from those of K07, K10, and K13, but the difference between the maximum swelling and the swelling at 28 days (i.e., ε2) is similar for OPC, K07, K10, and K13. Experimentally, ε2 has been found to be approximately 1531 με for OPC-based SDMCC and 605 με for LC3-based SDMCC. Therefore, for OPC-based SDMCC, the maximum swelling ε1 = ε2 / k is preferably at least 3062 με (1531 / 0.5) to achieve the desired binding effect. The maximum swelling of LC3-based SDMCC is preferably at least 1210 με (605 / 0.5).

[0096] 3. Fabrication of prefabricated rectangular pillar members using multi-layer cementitious compositions

[0100] Prefabricated prismatic members of multilayer cementitious compositions can be manufactured by selecting the appropriate composition, as exemplified in Table 1. For example, R13-C15 achieves a long-term shrinkage of 326 με and is therefore suitable for use as an outer layer. OPC also shrinks, but its long-term shrinkage of 1434 με can lead to cracking, which is undesirable. For inner layers, controlled-expansion materials are desirable. LC3-K13 exhibits a long-term expansion of 1722 με and can serve as this inner layer.

[0097]

[0101] Where reference has been made herein to a patent specification, another external document, or another source of information, this is generally for the purpose of providing a context for discussing features of the present invention. Unless specifically stated, the reference to such an external document should not be construed as an admission that such document or such source of information is prior art or forms part of the common general knowledge in the art in any jurisdiction.

[0098]

[0102] It is not intended that the scope of the present invention be limited solely to the above examples. As will be appreciated by those skilled in the art, many variations are possible without departing from the scope of the present invention as set forth in the appended claims.

Claims

1. an inner layer comprising a first cementitious material; An outer layer; A composite member comprising: the inner layer substantially covers an inner surface of the outer layer, and the first cementitious material is an expansive material that exerts a force against the inner surface of the outer layer. Composite material.

2. A method for manufacturing a composite member according to claim 1, spraying the unhardened mixture of the first cementitious material onto the inner surface of the outer layer; hardening the first cementitious material to obtain the composite member; A method comprising:

3. 1. A method for manufacturing a composite member, comprising: an inner layer including a first cementitious material that expands when hardened; a formwork layer; and an outer layer, wherein the inner layer is in contact with an outer surface of the formwork layer and an inner surface of the outer layer, providing the form layer and the outer layer with an air gap between the two layers; injecting the unhardened mixture of the first cementitious material into the gap between the form layer and the outer layer; hardening the first cementitious material to obtain the composite member; A method comprising:

4. 4. The composite member of claim 1 or the method of claim 2 or 3, wherein the first cementitious material comprises an expanding agent.

5. 5. The composite member of claim 1 or 4, or the method of any one of claims 2, 3, or 4, wherein the first cementitious material exhibits a maximum expansion of at least about 1200 με.

6. A composite member according to any one of claims 1, 4 or 5 or a method according to any one of claims 2 to 5, wherein the outer layer comprises a second cementitious material.

7. 7. A composite member or method according to claim 6, wherein said second cementitious material shrinks upon hardening.

8. 8. A composite member or method according to claim 6 or 7, wherein the second cementitious material exhibits shrinkage of less than about 500 μm upon hardening.

9. 8. A composite member or method according to claim 6 or 7, wherein the second cementitious material exhibits shrinkage upon hardening of less than about 1000 με.

10. A composite member or method according to any one of claims 6 to 9, wherein the first cementitious material and / or the second cementitious material comprises a composite binder.

11. 11. The composite member or method of claim 10, wherein the composite binder comprises a cement component and a pozzolanic component.

12. A composite member or method according to any one of claims 6 to 11, wherein the first cementitious material and / or the second cementitious material comprises fibres.

13. A composite member or method according to any one of claims 6 to 12, wherein the first cementitious material and / or the second cementitious material are sprayable.

14. 6. The composite member of claim 1, 4 or 5, or the method of claim 2, 3 or 4, wherein the outer layer comprises a metal, a polymer, a composite material, or a combination of any two or more thereof.

15. The method of claim 3 , wherein the form layer comprises a metal, a polymer, a composite material, or a combination of any two or more thereof.

16. A composite element according to any one of claims 1 or 4 to 15, or a method according to any one of claims 2 to 15, wherein the composite element is prefabricated.

17. A composite member according to any one of claims 1 or 4 to 16, or a method according to any one of claims 2 to 16, wherein the composite member is hollow or solid.

18. A composite element according to any one of claims 1 or 4 to 17, or a method according to any one of claims 2 to 17, wherein the composite element is in the shape of a tube, a column or a slab.

19. A composite member produced by the method according to any one of claims 2 to 18.

20. 20. Use of a composite member according to any one of claims 1 or 4 to 19 as a tube, wherein said composite member is hollow.

21. 21. The use according to claim 20, wherein the cross section of the composite member is circular.

22. 22. The use according to claim 20 or 21, wherein the pipe is for transporting water, gas or oil.

23. Use of a composite element according to any one of claims 1 or 4 to 19 as a building element.

24. 24. The use according to claim 23, wherein the building element is a column or a slab.

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