Low-carbon high-strength wading cement-based composite material as well as preparation method and application thereof

Abstract

The invention discloses a low-carbon high-strength wading cement-based composite material as well as a preparation method and application thereof, and belongs to the technical field of plateau high-cold hydraulic building materials. The cement-based composite material contains cement, silica fume, calcined clay, limestone powder, gypsum, fine sand, water, fibers, a water reducing agent, a defoaming agent, an expanding agent and the like. The low-carbon high-performance wading cement-based composite material with the strength higher than 100 MPa and the ultimate tensile strain exceeding 3% is designed on the basis of a calcined clay-limestone powder-gypsum gelling system and an ECC theory, meanwhile, the anti-freezing grade of the cement-based composite material reaches F500, and the anti-abrasion strength is about 5-7 times that of traditional hydraulic concrete. When the material is used for the plateau wading hydraulic concrete structure, the anti-freezing and abrasion-resistant performance of the hydraulic concrete structure can be improved, and the service life of the hydraulic concrete structure in the plateau wading environment can be prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic construction materials in high altitude and cold regions, and specifically relates to a low-carbon and high-strength water-related cement-based composite material, and a preparation method and application thereof. Background Art

[0002] The Qinghai-Tibet Plateau region has a severe environment with a daily temperature difference of more than 30°C, strong radiation, and dry climate, which causes the durability of concrete to drop sharply. Among them, freeze-thaw damage and abrasion damage are the two most significant forms of degradation of wading bridge piers, resulting in the gradual loss of concrete quality and the disintegration of bearing capacity. Although the addition of silica fume, rubber aggregate and steel fiber are beneficial to improving the impact and abrasion resistance of concrete, its impact and abrasion resistance still deteriorates sharply when the wading is damaged by internal freeze-thaw damage. Furthermore, as a seismic zone with frequent seismic activity, the Qinghai-Tibet Plateau requires cement-based composite materials to have not only environmental durability but also significant seismic toughness.

[0003] Engineered cementitious composites (ECC) have high ductility and excellent crack control ability, and they have broad prospects as seismic materials. However, ordinary ECC usually shows a compressive strength of less than 60MPa, and its freeze-thaw resistance is difficult to reach F300. Therefore, it is urgent to develop high-performance (>80MPa) ECC to solve the engineering and technical problems of high-altitude cold wading structures suffering from internal freeze-thaw damage and external river sand abrasion damage. However, based on the theoretical design of ECC, a low sand-to-binder ratio is usually used to obtain a suitable matrix fracture toughness, and the production of 1m 3 High-strength ECC will consume 1100-1500kg of cement, which will cause the release of a large amount of greenhouse gas CO2 and energy consumption. At the same time, this is not conducive to the promotion and application of high-strength ECC in hydraulic structures on the Qinghai-Tibet Plateau.

[0004] The ternary system of calcined clay-limestone powder-gypsum is composed of gypsum, limestone and calcined clay. Due to the volcanic ash reaction of kaolin in calcined clay and the synergistic effect of limestone and kaolin in the microstructure to produce monocarbon hydrated calcium aluminate and semi-carbon aluminate, limestone calcined clay cement can achieve the same strength as ordinary concrete in concrete. At the same time, the ternary cementitious system can replace part of the cement to reduce the carbon dioxide emissions in cement-based composite materials, which is in line with the sustainable development of green building materials. There are few precedents for using the ternary system of calcined clay-limestone powder-gypsum to replace cement in the preparation of high-strength ECC in the current research results. The fiber used by the researchers is 6mm PE, which is difficult to achieve the high ductility target. Importantly, there is no report on the use of limestone calcined clay cement to prepare ECC with antifreeze and wear resistance. Summary of the invention

[0005] In view of the above-mentioned prior art, the present invention provides a high-performance water-related cement-based composite material that is both frost-resistant, wear-resistant and low-carbon, and its preparation method and application, so as to solve the technical problems of poor frost resistance and abrasion resistance of existing water-related hydraulic concrete. At the same time, the cement-based composite material has the excellent characteristics of low carbon and green.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a low-carbon, high-strength water-related cement-based composite material, comprising the following components in parts by weight: 77 to 119 parts of cement, 19 parts of silica fume, 13.5 to 40.5 parts of calcined clay, 6.7 to 20 parts of limestone powder, 0.8 to 2.5 parts of gypsum, 48 parts of fine sand, 30 parts of water, 1.7 parts of fiber, 3 parts of water reducer, 0.5 parts of defoamer and 3.2 parts of expansion agent.

[0007] Based on the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, the cement is silicate cement with a strength grade of 42.5 or 52.5; and the silicon dioxide content in the silica fume is not less than 96%.

[0009] Furthermore, the calcined clay is obtained by calcining clay at a temperature of 650-800°C, and the kaolinite content thereof is not less than 55%; the particle size of the calcined clay is between 0.1 and 22 μm, and the specific surface area is between 2.00 and 2.42 m 2 / g, specific gravity is 2.40~2.53g / cm 3 .

[0010] Furthermore, the content of calcium carbonate in the limestone powder is not less than 70%, the particle size is 0.1 to 14 μm, and the specific surface area is 2.0 to 2.35 m 2 / g, specific gravity is 2.50~2.73g / cm 3 .

[0011] Furthermore, the content of calcium sulfate dihydrate in the gypsum is not less than 95%, and the particle size is 0.1 to 100 μm.

[0012] Furthermore, the fine sand is quartz sand with a particle size of 0.075 to 0.38 mm and a fineness modulus of 1.4 to 1.6.

[0013] Furthermore, the fiber is a polyethylene fiber, having a length of 12 to 18 mm, an equivalent diameter of 26 to 40 μm, and a specific gravity of 0.95 to 0.97 g / cm 3 , tensile modulus is 100~200GPa, and tensile strength is 3000~5000MPa.

[0014] Furthermore, the water reducing agent is a polycarboxylic acid type water reducing agent, and the water reducing rate is greater than 40%; the defoaming agent is a polyether type defoaming agent, and its density is 0.95-1.05 g / cm 3 The expansion agent is AEA type calcium sulphoaluminate expansion agent, and its density is 2.6~2.8g / cm 3 .

[0015] The present invention also discloses a method for preparing the low-carbon high-strength water-resistant cement-based composite material, comprising the following steps:

[0016] S1: dry-mix the formulated amount of cement, silica fume, calcined clay, limestone powder, gypsum, fine sand, defoamer and expansion agent in a mixing barrel for 5 to 8 minutes to obtain a mixture; the dry-mixing speed is 300 to 360 rpm;

[0017] S2: Add the water reducer into the water and stir evenly, then pour the mixed liquid of water and water reducer into the mixing bucket, mix it with the mixed material, and stir it at a speed of 300-360rpm for 3-5min;

[0018] S3: Add the fiber into a stirring barrel and stir at a speed of 540-600 rpm for 5-6 minutes to obtain a slurry;

[0019] S4: Place the slurry into a mold and demould it after 24 to 48 hours.

[0020] The present invention also discloses the use of the low-carbon high-strength water-related cement-based composite material as an antifreeze and wear-resistant layer for water-related hydraulic structures in high-altitude and cold regions.

[0021] The beneficial effects of the present invention are:

[0022] 1. The low-carbon, high-performance water-related cement-based composite material prepared by the present invention has low carbon emissions, because the present invention adopts a limestone calcined clay gelling system, and the calcination temperature of the calcined clay in the raw materials is only 650-800°C, which is much lower than the cement calcination temperature of 1450°C, resulting in low energy consumption and low carbon emissions. Therefore, the energy consumption for preparing low-carbon, high-strength hydraulic engineering cement-based composite materials is lower, and CO2 emissions are less, which is a low-carbon, green, high-ductility cement-based composite material. The unit CO2 emissions and energy consumption of the low-carbon hydraulic high-ductility cement of the present invention are reduced by 12% to 35.5% respectively compared with traditional high-strength and high-ductility cement-based composite materials.

[0023] 2. The low-carbon, high-performance water-based cement-based composite material prepared by the present invention has a compressive strength of 92 to 112 MPa, a tensile strength and an ultimate tensile strain of 8.6 to 9.3 MPa and 4.0 to 5.2%, respectively, and its antifreeze grade is higher than F500.

[0024] 3. The low-carbon high-performance water-based cement-based composite material prepared by the present invention has an anti-abrasion strength of 136.5 to 190.7 h·(kg / m 2 ) -1 , much higher than the 25.1h·(kg / m 2 ) -1 The low-carbon, high-performance water-resistant cement-based composite material prepared by the present invention can effectively solve the problem of the rapid reduction in durability of water-resistant hydraulic structures in the high-cold areas of the Qinghai-Tibet Plateau during the freeze-thaw and abrasion process.

[0025] 4. The low-carbon, high-performance water-based cement-based composite material slurry prepared by the present invention has an expansion degree of 210 to 230 mm, and its working performance meets the requirements of on-site casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a comparison chart of the 28-day compressive strength of the materials in Examples 1 to 3 and Comparative Examples 1 to 2;

[0027] Figure 2 It is a uniaxial tensile stress-strain curve diagram of the materials in Examples 1 to 3 and Comparative Example 2;

[0028] Figure 3 is the CO2 release of the materials in Examples 1 to 3 and Comparative Example 2;

[0029] Figure 4 The graphs are the dynamic elastic modulus-freeze-thaw cycle number variation graphs of the materials in Examples 1 to 3 and Comparative Examples 1 to 2;

[0030] Figure 5 It is a comparison chart of the abrasion resistance of the materials in Examples 1 to 3 and Comparative Examples 1 to 2;

[0031] Figure 6 This is a comparison of the apparent morphologies of the materials in Examples 1 to 3 and Comparative Examples 1 to 2 after 72 hours of grinding. DETAILED DESCRIPTION

[0032] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0033] Example 1

[0034] A low-carbon high-strength water-resistant cement-based composite material, comprising the following components in parts by weight:

[0035] 119 parts of cement, 19 parts of silica fume, 13.5 parts of calcined clay, 6.8 parts of limestone powder, 0.8 parts of gypsum, 48 parts of fine sand, 30 parts of water, 1.7 parts of fiber, 3 parts of water reducer, 0.5 parts of defoamer and 3 parts of expansion agent.

[0036] in,

[0037] The cement used is ordinary Portland cement with a strength grade of 52.5; the silica fume used is silica fume with a silicon dioxide content of about 97%; the limestone powder used is limestone powder with a calcium carbonate content of about 80%, with a particle size of 0.1 to 14 μm (mixed by limestone powder with a particle size of 0.1 to 14 μm in a continuous grading manner), and a specific surface area of ​​2.0 m 2 / g, specific gravity is 2.50g / cm 3 The gypsum used is gypsum powder with a calcium sulfate dihydrate content of about 96%, and its particle size is between 0.1 and 100 μm (mixed by gypsum powder with a particle size of 0.1 to 100 μm in a continuous grading manner); the fine sand used is quartz sand, with a particle size of 0.075 to 0.38 mm (mixed by quartz sand with a particle size of 0.075 to 0.38 mm in a continuous grading manner), and a fineness modulus of 1.5; the fiber used is polyethylene fiber, with a length of 15 mm, an equivalent diameter of 30 μm, and a specific gravity of 0.96 g / cm 3 , tensile modulus is 1150GPa, tensile strength is 4000MPa; the water reducer used is a polycarboxylic acid water reducer with a water reduction rate greater than 40% (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the defoamer used is a polyether defoamer (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the expansion agent used is an AEA type calcium sulphoaluminate expansion agent (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.). The calcined clay used is prepared by the following steps:

[0038] Take clay, heat it to 700℃, and calcine it for 2h to obtain calcined clay with a kaolinite content of about 60%; then grind the calcined clay into particles with a particle size of 0.1 to 22μm (mixed by continuous grading of clay powders with a particle size of 0.1 to 22μm) and a specific surface area of ​​2.20m 2 / g, specific gravity is 2.50g / cm 3 of powder.

[0039] The low-carbon high-strength water-resistant cement-based composite material in this embodiment is prepared by the following steps:

[0040] S1: dry mix the formulated amount of cement, silica fume, calcined clay, limestone powder, gypsum, fine sand, defoamer and expansion agent in a mixing barrel for 5 minutes to obtain a mixture; the dry mixing speed is 300 rpm;

[0041] S2: Add the water reducer into the water and stir evenly, then pour the mixed liquid of water and water reducer into the mixing bucket, mix it with the mixed material, and stir it at a speed of 300 rpm for 5 minutes;

[0042] S3: Add the fiber into a stirring barrel, stir at a stirring rate of 360 rpm for 5 min, and then stir at a stirring rate of 550 rpm for 5 min to obtain a slurry;

[0043] S4: Place the slurry into a mold, remove the mold after 48 hours, and then cure it in an environment with a temperature of 20±2℃ and a humidity of>95% for 28 days.

[0044] Example 2

[0045] A low-carbon high-strength water-resistant cement-based composite material, comprising the following components in parts by weight:

[0046] 98.5 parts of cement, 19 parts of silica fume, 27 parts of calcined clay, 13.5 parts of limestone powder, 1.7 parts of gypsum, 48 parts of fine sand, 30 parts of water, 1.7 parts of fiber, 3 parts of water reducer, 0.5 parts of defoamer and 3 parts of expansion agent.

[0047] in,

[0048] The cement used is ordinary Portland cement with a strength grade of 52.5; the silica fume used is silica fume with a silicon dioxide content of about 98%; the limestone powder used is limestone powder with a calcium carbonate content of about 75%, with a particle size of 0.1 to 14 μm (mixed by limestone powder with a particle size of 0.1 to 14 μm in a continuous grading manner), and a specific surface area of ​​2.35 m 2 / g, specific gravity is 2.73g / cm 3 The gypsum used is gypsum powder with a calcium sulfate dihydrate content of about 97%, and its particle size is between 0.1 and 100 μm (mixed by gypsum powder with a particle size of 0.1 to 100 μm in a continuous grading manner); the fine sand used is quartz sand, with a particle size of 0.075 to 0.38 mm (mixed by quartz sand with a particle size of 0.075 to 0.38 mm in a continuous grading manner), and a fineness modulus of 1.4; the fiber used is polyethylene fiber, with a length of 18 mm, an equivalent diameter of 40 μm, and a specific gravity of 0.97 g / cm 3 , tensile modulus is 200GPa, tensile strength is 5000MPa; the water reducer used is a polycarboxylic acid water reducer with a water reduction rate greater than 40% (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the defoamer used is a polyether defoamer (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the expansion agent used is an AEA type calcium sulfoaluminate expansion agent (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.). The calcined clay used is prepared by the following steps:

[0049] Take clay, heat it to 650°C, and calcine it for 4 hours to obtain calcined clay with a kaolinite content of about 55%; then grind the calcined clay into particles with a size of 0.1 to 22 μm (mixed by continuous grading of clay powders with a particle size of 0.1 to 22 μm) and a specific surface area of ​​2.00 m 2 / g, specific gravity is 2.40g / cm 3 of powder.

[0050] The low-carbon high-strength water-resistant cement-based composite material in this embodiment is prepared by the following steps:

[0051] S1: dry mix the formulated amount of cement, silica fume, calcined clay, limestone powder, gypsum, fine sand, defoamer and expansion agent in a mixing barrel for 5 minutes to obtain a mixture; the dry mixing speed is 300 rpm;

[0052] S2: Add the water reducer into the water and stir evenly, then pour the mixed liquid of water and water reducer into the mixing bucket, mix it with the mixed material, and stir it at a speed of 300 rpm for 5 minutes;

[0053] S3: Add the fiber into a stirring barrel, stir at a stirring rate of 360 rpm for 5 min, and then stir at a stirring rate of 540 rpm for 5 min to obtain a slurry;

[0054] S4: Place the slurry into a mold, remove the mold after 48 hours, and then cure it in an environment with a temperature of 20±2℃ and a humidity of>95% for 28 days.

[0055] Example 3

[0056] A low-carbon high-strength water-resistant cement-based composite material, comprising the following components in parts by weight:

[0057] 77 parts of cement, 19 parts of silica fume, 41 parts of calcined clay, 20 parts of limestone powder, 2.5 parts of gypsum, 48 parts of fine sand, 30 parts of water, 1.7 parts of fiber, 3 parts of water reducer, 0.5 parts of defoamer and 3 parts of expansion agent. Among them,

[0058] The cement used is ordinary Portland cement with a strength grade of 52.5; the silica fume used is silica fume with a silicon dioxide content of about 96%; the limestone powder used is limestone powder with a calcium carbonate content of about 70%, with a particle size of 0.1 to 14 μm (mixed by limestone powder with a particle size of 0.1 to 14 μm in a continuous grading manner), and a specific surface area of ​​2.0 m 2 / g, specific gravity is 2.5g / cm 3The gypsum used is gypsum powder with a calcium sulfate dihydrate content of about 95%, and its particle size is between 0.1 and 100 μm (mixed by gypsum powder with a particle size of 0.1 to 100 μm in a continuous grading manner); the fine sand used is quartz sand, with a particle size of 0.075 to 0.38 mm (mixed by quartz sand with a particle size of 0.075 to 0.38 mm in a continuous grading manner), and a fineness modulus of 1.6; the fiber used is polyethylene fiber, with a length of 12 mm, an equivalent diameter of 26 μm, and a specific gravity of 0.95 g / cm 3 , tensile modulus is 100GPa, tensile strength is 3000MPa; the water reducer used is a polycarboxylic acid type water reducer with a water reduction rate greater than 40% (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the defoamer used is a polyether type defoamer (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the expansion agent used is an AEA type calcium sulfoaluminate expansion agent (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.). The calcined clay used is prepared by the following steps:

[0059] Take clay, heat it to 800℃, and calcine it for 1h to obtain calcined clay with a kaolinite content of about 65%; then grind the calcined clay into particles with a particle size of 0.1 to 22μm (mixed by continuous grading of clay powders with a particle size of 0.1 to 22μm) and a specific surface area of ​​2.42m 2 / g, specific gravity is 2.53g / cm 3 of powder.

[0060] The low-carbon high-strength water-resistant cement-based composite material in this embodiment is prepared by the following steps:

[0061] S1: dry mix the formulated amount of cement, silica fume, calcined clay, limestone powder, gypsum, fine sand, defoamer and expansion agent in a mixing barrel for 5 minutes to obtain a mixture; the dry mixing speed is 300 rpm;

[0062] S2: Add the water reducer into the water and stir evenly, then pour the mixed liquid of water and water reducer into the mixing bucket, mix it with the mixed material, and stir it at a speed of 300 rpm for 5 minutes;

[0063] S3: Add the fiber into a stirring barrel, stir at a stirring rate of 360 rpm for 5 min, and then stir at a stirring rate of 540 rpm for 5 min to obtain a slurry;

[0064] S4: Place the slurry into a mold, remove the mold after 48 hours, and then cure it in an environment with a temperature of 20±2℃ and a humidity of>95% for 28 days.

[0065] Comparative Example 1

[0066] A C40 concrete comprising the following components in parts by weight:

[0067] 30 parts of cement, 18 parts of fly ash, 78 parts of river sand, 87 parts of coarse aggregate, 22.3 parts of water, 1 part of water reducer. Among them,

[0068] The cement used is ordinary Portland cement with a strength grade of 42.5; the fly ash used is Class I fly ash; the river sand used has a fineness modulus of 2.5 to 2.6; the coarse aggregate particle size is 5 to 20 mm; the water reducer used is a polycarboxylic acid type water reducer with a water reduction rate greater than 40% (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.).

[0069] Comparative Example 2

[0070] A low-carbon high-strength water-resistant cement-based composite material, comprising the following components in parts by weight:

[0071] 141 parts of cement, 19 parts of silica fume, 48 parts of fine sand, 30 parts of water, 1.7 parts of fiber, 3 parts of water reducer, 0.5 parts of defoamer and 3 parts of expansion agent. Among them,

[0072] The cement used is ordinary Portland cement with a strength grade of 52.5; the silica fume used is silica fume with a silicon dioxide content of about 97%; the fine sand used is quartz sand with a particle size of 0.075-0.38 mm and a fineness modulus of 1.5; the fiber used is polyethylene fiber with a length of 15 mm, an equivalent diameter of 30 μm, and a specific gravity of 0.96 g / cm 3 , tensile modulus is 1150GPa, and tensile strength is 4000MPa; the water reducer used is a polycarboxylic acid type water reducer with a water reduction rate greater than 40% (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the defoamer used is a polyether type defoamer (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.); the expansion agent used is an AEA type calcium sulfoaluminate expansion agent (purchased from Beijing Dechang Weiye Construction Engineering Technology Co., Ltd.).

[0073] The low-carbon high-strength water-resistant cement-based composite material in this comparative example is prepared by the following steps:

[0074] S1: dry mix the formulated amount of cement, silica fume, fine sand, defoamer and expansion agent in a mixing barrel for 5 minutes to obtain a mixture; the dry mixing speed is 300 rpm;

[0075] S2: Add the water reducer into the water and stir evenly, then pour the mixed liquid of water and water reducer into the mixing bucket, mix it with the mixed material, and stir it at a speed of 300 rpm for 5 minutes;

[0076] S3: Add the fiber into a stirring barrel, stir at a stirring rate of 360 rpm for 5 min, and then stir at a stirring rate of 550 rpm for 5 min to obtain a slurry;

[0077] S4: Place the slurry into a mold, remove the mold after 48 hours, and then cure it in an environment with a temperature of 20±2℃ and a humidity of>95% for 28 days.

[0078] Experimental example

[0079] The mechanical properties of the materials in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, and the results are shown in Table 1.

[0080] Table 1 Mechanical properties of materials

[0081]

[0082] Comparison of 28-day compressive strength of the materials in Examples 1 to 3 and Comparative Examples 1 to 2 Figure 1 As shown in the figure, it can be seen that with the increase in the amount of limestone-calcined clay-gypsum cementitious system, the compressive strength of Examples 1 and 2 is almost equivalent to that of Comparative Example 2, and the compressive strength of Example 3 is about 15.8% lower than that of Comparative Example 2. The tensile strength of the three groups of examples after 28 days is more than 90MPa. The uniaxial tensile stress-strain curves of the materials in Examples 1 to 3 and Comparative Example 2 are shown in Figure 2 As shown in the figure, it can be seen that with the increase of the amount of limestone-calcined clay-gypsum cementitious system, the ultimate tensile strain of Example 28 gradually increases, indicating that the limestone-calcined clay-gypsum cementitious system of the present invention is beneficial to increase the ultimate tensile strain of the matrix. The CO2 release of the materials in Examples 1 to 3 and Comparative Example 2 is as follows Figure 3 As shown in the figure, it can be seen that the CO2 release of Example 3 is 923.9 kg / t, which is 35.5% lower than that of Comparative Example 2, greatly reducing the carbon emissions of low-carbon and high-strength hydraulic engineering cement-based composite materials, making the preparation of this material more green and environmentally friendly.

[0083] The dynamic elastic modulus of the materials in Examples 1 to 3 and Comparative Examples 1 to 2 changes in the number of freeze-thaw cycles as shown in Figure 4 As shown in the figure, it can be seen that the relative dynamic elastic modulus of the hydraulic C40 (Comparative Example 1) commonly used in engineering is less than <53% after 300 freeze-thaw cycles, while the low-carbon, high-performance water-related cement-based composite materials (Examples 1-3) of the present invention show good antifreeze performance, all of which can reach F500. The abrasion resistance of the materials in Examples 1-3 and Comparative Examples 1-2 is shown in Figure 5 As shown in the figure, it can be seen that compared with Comparative Example 2, as the amount of limestone-calcined clay-gypsum cementitious system increases, the matrix abrasion resistance gradually decreases, but compared with Comparative Example 1, the abrasion resistance of Examples 1 to 3 is still about 5 to 8 times that of Comparative Example 1, showing better abrasion resistance. The apparent morphology of the materials in Examples 1 to 3 and Comparative Examples 1 to 2 after abrasion for 72 hours is as follows Figure 6As shown in the figure, it can be seen that after 72 hours of impact and abrasion, the surface morphology of the test pieces of Examples 1 to 3 and Comparative Example 2 is almost unchanged, but the surface slurry in Comparative Example 1 is abraded away, and the coarse aggregate is exposed on the surface. Therefore, the low-carbon, high-performance water-resistant cement-based composite material of the present invention has good anti-freezing and anti-impact properties, and can greatly improve the durability of water-resistant bridge piers and hydraulic channels in the Qinghai-Tibet Plateau and extend their service life.

[0084] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments and drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A low-carbon, high-strength water-resistant cement-based composite material, characterized in that: The invention comprises the following components in parts by weight: 77-119 parts of cement, 19 parts of silica fume, 13.5-41 parts of calcined clay, 6.7-20 parts of limestone powder, 0.8-2.5 parts of gypsum, 48 parts of fine sand, 30 parts of water, 1.7 parts of fiber, 3 parts of water reducing agent, 0.5 parts of defoaming agent and 3.2 parts of expansion agent.

2. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The cement is silicate cement with a strength grade of 42.5 or 52.5; the silicon dioxide content in the silica ash is not less than 96%.

3. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The calcined clay is obtained by calcining clay at a temperature of 650-800°C, and the kaolinite content thereof is not less than 55%; the particle size of the calcined clay is between 0.1 and 22 μm, and the specific surface area is between 2.00 and 2.42 m 2 / g, specific gravity is 2.40~2.53g / cm 3 .

4. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The content of calcium carbonate in the limestone powder is not less than 70%, the particle size is between 0.1 and 14 μm, and the specific surface area is between 2.0 and 2.35 m 2 / g, specific gravity is 2.50~2.73g / cm 3 .

5. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The content of calcium sulfate dihydrate in the gypsum is not less than 95%, and the particle size is between 0.1 and 100 μm.

6. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The fine sand is quartz sand with a particle size of 0.075 to 0.38 mm and a fineness modulus of 1.4 to 1.

6.

7. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The fiber is a polyethylene fiber with a length of 12 to 18 mm, an equivalent diameter of 26 to 40 μm, and a specific gravity of 0.95 to 0.97 g / cm 3 , tensile modulus is 100~200GPa, and tensile strength is 3000~5000MPa.

8. The low-carbon, high-strength water-resistant cement-based composite material according to claim 1, characterized in that: The water reducing agent is a polycarboxylic acid type water reducing agent, and the water reducing rate is greater than 40%; the defoaming agent is a polyether type defoaming agent; and the expansion agent is an AEA type calcium sulphoaluminate expansion agent.

9. The method for preparing the low-carbon high-strength water-resistant cement-based composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: dry-mix the formulated amount of cement, silica fume, calcined clay, limestone powder, gypsum, fine sand, defoamer and expansion agent in a mixing barrel for 5 to 8 minutes to obtain a mixture; the dry-mixing speed is 300 to 360 rpm; S2: Add the water reducer into the water and stir evenly, then pour the mixed liquid of water and water reducer into the mixing bucket, mix it with the mixed material, and stir it at a speed of 300-360rpm for 3-5min; S3: Add the fiber into a stirring barrel and stir at a speed of 540-600 rpm for 5-6 minutes to obtain a slurry; S4: Place the slurry into a mold and demould it after 24 to 48 hours.

10. Use of the low-carbon, high-strength water-related cement-based composite material according to any one of claims 1 to 8 as an antifreeze and wear-resistant layer for water-related hydraulic structures in high-altitude and cold regions.

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