JP-7854933-B2 - Sprayed cement-based composition

Inventors

• リー，ヴィクター シー．
• ソー，チュン ワイ
• ジュー，ヘ

Assignees

• ソー，チュン ワイ

Dates

Publication Date

20260507

Application Date

20200514

Priority Date

20200218

Claims (20)

1. A spray-applied cement-based composition comprising a composite binder, fibers, and water, wherein the composite binder comprises a cement component and a pozzolanic component, the cement component comprises hydraulic cement , a reactive aluminosilicate, calcium carbonate, and an expander, and the amount of the expander is approximately 32 to approximately 60% by weight based on the total weight of the cement component. The sprayed cement-based composition, upon hardening, achieves a maximum expansion of at least about 1210 με, its expansion after 28 days exceeds 50% of the maximum expansion, and it has a tensile strain capacity of at least about 3% after 28 days. A spray-applied cement-based composition.
2. The spray-applied cement-based composition according to claim 1, wherein the ratio of water to the composite binder is approximately 0.2 to approximately 0.5.
3. The spray-applied cement-based composition according to claim 1, wherein the expansive agent is calcium sulfoaluminate.
4. The spray-applied cement-based composition according to any one of claims 1 to 3, wherein the amount of the expansive agent is approximately 32 to approximately 50% by weight, based on the total weight of the cement components.
5. The spray-applied cement-based composition according to any one of claims 1 to 4, wherein the hydraulic cement comprises ordinary Portland cement.
6. The spray-applied cement-based composition according to any one of claims 1 to 5, wherein the amount of the hydraulic cement is approximately 1 to approximately 80% by weight, based on the total weight of the cement components.
7. The spray cement-based composition according to any one of claims 1 to 6 , wherein the reactive aluminosilicate is calcined clay.
8. The spray cement-based composition according to any one of claims 1 to 7 , wherein the calcium carbonate is limestone.
9. The spray-applied cement-based composition according to any one of claims 1 to 8 , wherein the amount of the pozzolanic component is about 1 to about 3 times the amount of the cement component, based on weight.
10. The spray cement composition according to any one of claims 1 to 9, wherein the pozzolanic component comprises a material selected from the group consisting of fly ash, steelmaking slag, granular blast furnace slag, calcined clay such as diatomaceous earth, silica fume, and metakaolin, calcined silica-rich organic matter such as calcined shale, volcanic ash, pumice, and rice husk ash, and mixtures of any two or more thereof.
11. The spray cement composition according to claim 10 , wherein the fly ash is selected from the group consisting of type C fly ash, type F fly ash, and mixtures thereof.
12. The spray cement composition according to any one of claims 1 to 11 , wherein the fiber is selected from the group consisting of polymer fibers, inorganic fibers, metal fibers, carbon fibers, plant fibers, and mixtures of two or more thereof.
13. The spray cement composition according to claim 12 , wherein the polymer fiber comprises a polymer material selected from the group consisting of polyolefins, polyacrylics, polyesters, polyvinyl alcohols, polyamides, and combinations of two or more thereof.
14. The spray cement composition according to claim 12 or 13 , wherein the polymer fiber is selected from the group consisting of polyethylene fiber, high-tenacity polypropylene fiber, polyvinyl alcohol fiber, and a mixture of two or more thereof.
15. The spray cement composition according to any one of claims 1 to 14 , wherein the spray cement composition further comprises one or more components selected from the group consisting of a fluidizer, aggregate, viscosity agent, and retarder.
16. When the sprayed cement-based composition hardens: (i) Tensile strength of at least about 2.50 MPa, ( ii ) A crack width of less than about 100 μm at ε < 2%, and one or more properties selected from the group consisting of the above , are achieved in the sprayed cement composition according to any one of claims 1 to 15 .
17. A method for preparing a spray cement-based composition according to any one of claims 1 to 16 , (i) To provide a binder composition containing cement components and pozzolanic components, (ii) Mixing the binder composition with water to form a wet mixture, (iii) Adding fibers to the wet mixture, A method comprising, wherein the cement components include hydraulic cement , reactive aluminosilicate, calcium carbonate, and an expander, and the amount of the expander is approximately 32 to approximately 60% by weight based on the total weight of the cement components.
18. The method according to claim 17 , further comprising mixing the cement component and the pozzolanic component to provide the binder composition.
19. The method according to claim 17 or 18 , wherein a fluidizing agent is added to the water before step (ii).
20. A method for repairing and/or improving a building structure, (i) the step of providing a spray cement composition according to any one of claims 1 to 16 ; (ii) spraying the cement-based composition onto the surface of the building structure to at least partially cover the surface with the cement-based composition; (iii) The step of setting the cement-based composition on the surface, Methods that include...

Description

[0001] The present invention relates to a sprayable ductile metal-like cementitious composition (SDMCC). The present invention also relates to the use of SDMCC for the repair or improvement of building structures such as underground pipelines, and to methods of using the same. [0002] Underground pipelines are extremely useful infrastructure and can be used for the transport and distribution of water for various purposes, such as drinking water and wastewater. Pipelines used for these purposes are often subjected to severe mechanical loads and environmental stresses. As a result, both metal and concrete pipes are prone to problems such as cracking, spalling, and debris accumulation. Metal pipes may also corrode or deform. If left unrepaired, these problems can lead to the failure of the pipeline. [0003] Trenchless pipeline repair techniques are useful for repairing existing pipelines with minimal damage. Lower construction costs, less environmental impact, and less disruption to the public mean that trenchless pipeline repair techniques are often preferable to open trench methods. Known trenchless pipeline repair methods include in-situ hardening pipe (CIPP), slip lining, close-fit pipe, spiral wound, splice segment lining, and spray lining. Compared to other methods, spray lining using cement-based materials offers advantages such as lower cost and faster construction. Spray lining can also be formed continuously without seams. [0004] The spray lining method involves spraying cement-based or polymer-based materials onto the inner surface of existing pipelines. Cement-based materials are low-cost but typically provide insufficient corrosion protection for steel host pipes. Polymer-based materials typically offer better corrosion resistance but are more expensive. After spraying onto the substrate, the material needs to have good adhesion and cohesiveness to deposit to the desired thickness. The inner surface of the pipeline is usually unsuitable for coating with the material. Although pipelines are usually cleaned before spraying, insufficient adhesion between the sprayed material and the inner wall of the pipe remains a major problem. [0005] Conventional cement-based materials are brittle and lack tensile ductility. To achieve high strength and a dense microstructure, cement-based repair materials typically require a low water content and a large amount of fine reactive powder. As a result of this combination, the cement-based material shrinks significantly, which can lead to constrained shrinkage cracking. After cracking, fluids in the pipeline penetrate the cracks and further corrode the pipe. Furthermore, if the adhesive strength is insufficient, the crack repair material may peel off. Therefore, using conventional cement-based materials often results in low durability of the repaired pipeline, requiring repeated maintenance. [0006] To overcome the inherent brittleness of cement-based materials, fiber-reinforced composites called high-toughness cement-based composites (ECCs) have been developed for spray-on repairs. ECCs exhibit high strain capacity exceeding 3% under uniaxial tension. The high ductility of ECCs is achieved by multiple dense cracks rather than the single cracks typical of ordinary concrete. However, ECC mixtures generally have a larger volume of cement and no coarse aggregate compared to ordinary concrete, and therefore drying shrinkage can reach -1500 με in 28 days. Increased shrinkage can lead to microcracks when deformation is constrained. The presence of microcracks in aggressive environments can affect the durability of spray-on repairs. Examples of ECCs are disclosed in the following patents. [0007] U.S. Patent No. 7,241,338 discloses a sprayed cement-based composition comprising a hydraulic cement such as Portland cement, a non-Newtonian additive, a viscosity agent, a fluidizer, short discontinuous fibers, lightweight aggregate, and water. [0008] U.S. Patent No. 7,572,501 discloses a cement-based composite material comprising cement such as Portland cement, water, sand, fly ash, a water-reducing agent, and discontinuous short fibers such as polyethylene (PE) fibers. The rheology of the composition can be adjusted to obtain a composite material that can be pumped, molded, or sprayed. [0009] U.S. Patent No. 7,799,127 discloses a type of polyvinyl alcohol (PVA) fiber-reinforced high-initial-hardness ECC material. This material comprises a hydraulic cement, a chemical accelerator mixture, polyvinyl alcohol fibers, a non-matrix interactive crack initiator, one or more fine aggregate particles, and a chemical dispersant mixture. [0010] The object of the present invention is to provide a method for avoiding the above-mentioned drawbacks and/or to provide at least a publicly useful alternative. [0011] Another object of the present invention will become apparent from the following description, which is provided merely as an example. [0012] Any discussion of literature, acts, materials, app