Low-cost C80 concrete and preparation method thereof

Abstract

The invention aims to provide low-cost C80 concrete and a preparation method thereof, and belongs to the technical field of building construction. Comprising the following components in parts by weight: 730 parts of P.O42.5 ordinary Portland cement, 27 to 28 parts of F-class II-grade fly ash, 71 to 75 parts of S95 slag powder, 78.5 to 94.2 parts of copper-plated microfilament type steel fiber, 739 to 790 parts of broken stone with a particle size range of 5 to 15 mm, 520 to 525 parts of sand with a fineness modulus of 2.4 to 2.8, 2.7 to 4.8 parts of a polycarboxylic acid high-performance water reducing agent and 210 to 240 parts of water. The concrete disclosed by the invention is relatively low in cost and also has good comprehensive performance.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, specifically relating to a low-cost C80 concrete and its preparation method. Background Technology

[0002] C80 concrete is a high-strength concrete with a compressive strength of 80 MPa, far exceeding that of ordinary concrete. Due to its high strength and excellent properties, C80 concrete is widely used in numerous fields. For example, it is the preferred material in infrastructure projects that require bearing enormous pressure and weight, such as large bridges, highways, and high-rise buildings. Furthermore, C80 concrete also plays an important role in water conservancy projects, tunnel construction, and marine engineering.

[0003] CN202110714763.2 discloses a crack-resistant C80 concrete and its preparation method. The crack-resistant C80 concrete includes: cement, mineral powder, medium sand, crushed stone, water, fly ash, polycarboxylate superplasticizer, sucrose ester, polyacrylamide, and benzoic acid.

[0004] CN202411425197.3 discloses a multi-scale toughened shrinkage-compensating C80 high crack-resistant self-compacting concrete and its preparation method. It uses low-shrinkage crack-resistant composite cement to compensate for the shrinkage of C80 concrete, avoiding the disadvantage that general expansion agents are difficult to play due to the low water-cement ratio design of ordinary C80 concrete, and solving the problem of easy shrinkage and cracking of C80 concrete.

[0005] CN202411425233.6 discloses a heat-shrinkable fiber mesh reinforced long-span box arch C80 high-toughness concrete and its preparation method. The method optimizes the composition and hydration process of the high-alumina phase cementitious material raw materials; applies uniform pre-stress inside the cementitious slurry by incorporating heat-shrinkable fibers; and toughens the C80 concrete material at the micron scale by incorporating CaCO3 whiskers. The method also toughens the C80 concrete material at the macro scale by incorporating copper-plated straight steel fibers and multi-anchor steel fibers.

[0006] Generally, C80 concrete typically uses high-quality cement, such as grade 52.5 cement, while the use of low-cost grade 42.5 ordinary cement is less common. While fine particles in fly ash and mineral powder can improve the microstructure of concrete and reduce porosity, thereby increasing its strength and durability, they can also affect its pumpability and increase the amount of water-reducing agent required, especially when using low-cost grade II or III fly ash with higher loss on ignition. Free calcium oxide in concrete increases porosity, damages its internal structure, leads to cracks, and reduces its strength and durability. Therefore, balancing the formation and consumption rates of free calcium oxide to the greatest extent possible is a crucial issue in the optimal design of concrete materials. Summary of the Invention

[0007] The purpose of this invention is to provide a low-cost C80 concrete and its preparation method, which has low cost and good comprehensive performance.

[0008] The present invention adopts the following technical solution: A low-cost C80 concrete comprises the following components in parts by weight: P.O42.5 ordinary Portland cement: 730 parts, Class II fly ash (F grade): 27-28 parts, S95 slag powder: 71-75 parts, copper-plated microfiber steel: 78.5-94.2 parts, crushed stone with a particle size range of 5-15mm: 739-790 parts, sand with a fineness modulus of 2.4-2.8: 520-525 parts, polycarboxylate superplasticizer: 2.7-4.8 parts, and water: 210-240 parts.

[0009] Furthermore, a low-cost C80 concrete comprises the following components in parts by weight: P.O42.5 ordinary Portland cement: 730 parts, Class II fly ash (F grade): 27 parts, S95 slag powder: 71 parts, copper-plated microfiber steel: 94.2 parts, crushed stone with a particle size range of 5-15mm: 757 parts, sand with a fineness modulus of 2.4-2.8: 522 parts, polycarboxylate high-performance water-reducing agent: 4.388 parts, and water: 217 parts.

[0010] A method for preparing low-cost C80 concrete includes the following steps: a. Add the specified weight proportions of Class F Grade II fly ash, S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly. b. Add the specified weight proportions of P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add the weight proportions of crushed stone with a particle size range of 5-15mm, copper-plated microfiber steel fibers, and an additional 50% water to the mixing drum and continue to mix thoroughly. d. Add the specified weight proportions of polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0011] Furthermore, a low-cost C80 concrete comprises the following components in parts by weight: P.O42.5 ordinary Portland cement: 730 parts, Class II fly ash (F grade): 27-28 parts, S95 slag powder: 71-75 parts, copper-plated microfiber steel: 78.5-94.2 parts, crushed stone with a particle size range of 5-15mm: 739-790 parts, sand with a fineness modulus of 2.4-2.8: 520-525 parts, polycarboxylate high-performance water-reducing agent: 2.7-4.8 parts, β-cyclodextrin: 1-2 parts, and water: 210-240 parts.

[0012] A method for preparing low-cost C80 concrete includes the following steps: a. Mix the specified weight proportions of Class F II fly ash, β-cyclodextrin, and 10% water thoroughly; then add the specified weight proportions of copper-plated microfiber steel fibers to obtain mixture A; b. Add the S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly. c. Add the specified weight proportions of P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; d. Add the crushed stone with a particle size range of 5-15mm, mixture A, and an additional 40% water to the mixing drum and continue to mix thoroughly. e. Add the specified weight proportions of polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0013] Furthermore, the Class F, Grade II fly ash has a loss on ignition of 1-3%, a fineness of 10-20%, a 28-day activity index of 75-80%, and a density of 2-2.5 g / cm³. 3 .

[0014] Furthermore, the density of the S95 slag powder is 2.85-3.05 g / cm³. 3 Specific surface area is 415-440 m² 2 / kg, with a flowability ratio of 100-110% and a 28-day activity index of 98-103%.

[0015] Furthermore, the copper-plated microfiber steel fiber has a tensile strength of 2500-3000MPa, a length of 10-13mm, an equivalent diameter of 0.15-0.25mm, and an aspect ratio of 40-85.

[0016] Furthermore, the mass percentage of needle-like and flaky particles in the crushed stone with a particle size range of 5-15 mm is 5-10%, and the saturated surface-dry apparent density is 2500-2650 kg / m³. 3 The saturated surface dry water absorption rate is 2-3%, the mass percentage of particles smaller than 10mm is 5.5-6.5%, and the crushing index is 9-12%.

[0017] Furthermore, the fineness modulus of the sand (2.4-2.8) has a particle size of less than 75 micrometers, with a mass percentage (stone powder content) of 6-8%, and a saturated surface-dry apparent density of 2500-2650 kg / m³. 3 The saturated surface dry water absorption rate is 2-3%, and the surface moisture content is 3-4%.

[0018] The beneficial effects of this invention are as follows: 1. This invention, by optimizing the ratio of slag powder and fly ash, can balance free calcium oxide, transforming it into a more stable mineral phase. Simultaneously, it optimizes the internal structure of concrete, fills concrete pores, and reduces the exposed area of ​​free calcium oxide, thereby reducing its reactivity, improving the impermeability and durability of concrete, and expanding the application range of P.O42.5 ordinary Portland cement.

[0019] 2. This invention improves the adsorption and dispersion of fly ash by treating it with β-cyclodextrin, thereby enhancing the homogeneity of concrete particles, reducing the amount of polycarboxylate superplasticizer, improving the workability of ready-mixed concrete, effectively controlling slump loss, improving the pumpability of concrete, reducing drying shrinkage, and expanding the application range of Class F, Grade II fly ash.

[0020] 3. The optimized formula ensures a stronger bond between the steel fibers and the matrix, significantly improving the crack resistance and compressive strength of concrete, as well as enhancing its toughness and impact resistance. This invention utilizes a low-cost, simple material formula, including P.O42.5 ordinary Portland cement and Class II fly ash (F grade), resulting in C80 concrete with significant technical and economic advantages. Detailed Implementation

[0021] The embodiments given below are intended to further illustrate the present invention, but should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0022] Example 1 A low-cost C80 concrete is made from the following raw materials in parts by weight: 730 parts of P.O42.5 ordinary Portland cement produced by Lanxi Chaofeng Cement Co., Ltd., a subsidiary of Hongshi Holding Group; 27 samples of Class F, Grade II fly ash, with the following specifications: loss on ignition 1-3%, fineness 10-20%, 28-day activity index 75-80%, and density 2-2.5 g / cm³. 3 ; 71 portions of S95 slag powder from Hebei Anfeng Iron and Steel Group Co., Ltd., with a density of 2.85-3.05 g / cm³. 3 Specific surface area 415-440m² 2 / kg, flowability ratio 100-110%, 28-day activity index 98-103%; Zhejiang Born Metal Products Co., Ltd. produces 94.2 parts of copper-plated microfiber steel, with the following specifications: tensile strength 2500-3000MPa, length 10-13mm, equivalent diameter 0.15-0.25mm, and aspect ratio 40-85. 757 parts of crushed stone with a particle size range of 5-15mm, with the following specifications: 5-10% by mass of needle-like and flaky particles, and 2500-2650 kg / m³ saturated surface-dry apparent density. 3 Saturated surface dry water absorption rate 2-3%, particle size less than 5mm mass percentage 1.8-2.2%, particle size less than 10mm mass percentage 5.5-6.5%, crushing index 9-12%; Fineness modulus 2.4-2.8, 522 parts of sand, with the following index: mass percentage of particles smaller than 75 micrometers (stone powder content) 6-8%, saturated surface-dry apparent density 2500-2650 kg / m³. 3 Saturated surface dry water absorption rate 2-3%, surface moisture content 3-4%; 4.388 parts of HQ-HPC polycarboxylate high-performance water-reducing agent produced by Hangzhou Shibao Building Materials Technology Co., Ltd. 217 portions of water.

[0023] The preparation method includes the following steps: a. Add Class F Grade II fly ash, S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly; b. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add crushed stone with a particle size range of 5-15mm, copper-plated micro-wire steel fiber and another 50% of water to the mixing drum and continue to mix thoroughly. d. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0024] Example 2 A low-cost C80 concrete is made from the following raw materials in parts by weight: 730 parts of P.O42.5 ordinary Portland cement produced by Lanxi Chaofeng Cement Co., Ltd., a subsidiary of Hongshi Holding Group; 27 samples of Class F, Grade II fly ash, with the following specifications: loss on ignition 1-3%, fineness 10-20%, 28-day activity index 75-80%, and density 2-2.5 g / cm³. 3 ; 71 portions of S95 slag powder from Hebei Anfeng Iron and Steel Group Co., Ltd., with a density of 2.85-3.05 g / cm³. 3 Specific surface area 415-440m² 2 / kg, flowability ratio 100-110%, 28-day activity index 98-103%; Zhejiang Born Metal Products Co., Ltd. produces 78.5 parts copper-plated microfiber steel fibers with the following specifications: tensile strength 2500-3000MPa, length 10-13mm, equivalent diameter 0.15-0.25mm, and aspect ratio 40-85. 739 parts of crushed stone with a particle size range of 5-15mm, with the following specifications: 5-10% by mass of needle-like and flaky particles, and 2500-2650 kg / m³ saturated surface-dry apparent density. 3 Saturated surface dry water absorption rate 2-3%, particle size less than 5mm mass percentage 1.8-2.2%, particle size less than 10mm mass percentage 5.5-6.5%, crushing index 9-12%; Fineness modulus 2.4-2.8, 520 parts of sand, with the following specifications: mass percentage of particles smaller than 75 micrometers (stone powder content) 6-8%, saturated surface-dry apparent density 2500-2650 kg / m³. 3 Saturated surface dry water absorption rate 2-3%, surface moisture content 3-4%; 3.9 parts of HQ-HPC polycarboxylate high-performance water-reducing agent produced by Hangzhou Shibao Building Materials Technology Co., Ltd. 210 portions of water.

[0025] The preparation method includes the following steps: a. Add Class F Grade II fly ash, S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly; b. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add crushed stone with a particle size range of 5-15mm, copper-plated micro-wire steel fiber and another 50% of water to the mixing drum and continue to mix thoroughly. d. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0026] Example 3 A low-cost C80 concrete is made from the following raw materials in parts by weight: 730 parts of P.O42.5 ordinary Portland cement produced by Lanxi Chaofeng Cement Co., Ltd., a subsidiary of Hongshi Holding Group; 28 samples of Class F, Grade II fly ash, with the following specifications: loss on ignition 1-3%, fineness 10-20%, 28-day activity index 75-80%, and density 2-2.5 g / cm³. 3 ; 75 parts of S95 slag powder from Hebei Anfeng Iron and Steel Group Co., Ltd., with a density of 2.85-3.05 g / cm³. 3 Specific surface area 415-440m² 2 / kg, flowability ratio 100-110%, 28-day activity index 98-103%; Zhejiang Born Metal Products Co., Ltd. produces 94.2 parts of copper-plated microfiber steel, with the following specifications: tensile strength 2500-3000MPa, length 10-13mm, equivalent diameter 0.15-0.25mm, and aspect ratio 40-85. 790 parts of crushed stone with a particle size range of 5-15mm, with the following specifications: 5-10% by mass of needle-like and flaky particles, and 2500-2650 kg / m³ saturated surface-dry apparent density. 3 Saturated surface dry water absorption rate 2-3%, particle size less than 5mm mass percentage 1.8-2.2%, particle size less than 10mm mass percentage 5.5-6.5%, crushing index 9-12%; Fineness modulus 2.4-2.8, 525 parts of sand, with the following specifications: mass percentage of particles smaller than 75 micrometers (stone powder content) 6-8%, saturated surface-dry apparent density 2500-2650 kg / m³. 3 Saturated surface dry water absorption rate 2-3%, surface moisture content 3-4%; 4.8 parts of HQ-HPC polycarboxylate high-performance water-reducing agent produced by Hangzhou Shibao Building Materials Technology Co., Ltd. 240 portions of water.

[0027] The preparation method includes the following steps: a. Add Class F Grade II fly ash, S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly; b. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add crushed stone with a particle size range of 5-15mm, copper-plated micro-wire steel fiber and another 50% of water to the mixing drum and continue to mix thoroughly. d. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0028] Example 4 A low-cost C80 concrete is made from the following raw materials in parts by weight: 730 parts of P.O42.5 ordinary Portland cement produced by Lanxi Chaofeng Cement Co., Ltd., a subsidiary of Hongshi Holding Group; 27 samples of Class F, Grade II fly ash, with the following specifications: loss on ignition 1-3%, fineness 10-20%, 28-day activity index 75-80%, and density 2-2.5 g / cm³. 3 ; 71 portions of S95 slag powder from Hebei Anfeng Iron and Steel Group Co., Ltd., with a density of 2.85-3.05 g / cm³. 3 Specific surface area 415-440m² 2 / kg, flowability ratio 100-110%, 28-day activity index 98-103%; Zhejiang Born Metal Products Co., Ltd. produces 78.5 parts copper-plated microfiber steel fibers with the following specifications: tensile strength 2500-3000MPa, length 10-13mm, equivalent diameter 0.15-0.25mm, and aspect ratio 40-85. 739 parts of crushed stone with a particle size range of 5-15mm, with the following specifications: 5-10% by mass of needle-like and flaky particles, and 2500-2650 kg / m³ saturated surface-dry apparent density. 3 Saturated surface dry water absorption rate 2-3%, particle size less than 5mm mass percentage 1.8-2.2%, particle size less than 10mm mass percentage 5.5-6.5%, crushing index 9-12%; Fineness modulus 2.4-2.8, 520 parts of sand, with the following specifications: mass percentage of particles smaller than 75 micrometers (stone powder content) 6-8%, saturated surface-dry apparent density 2500-2650 kg / m³. 3 Saturated surface dry water absorption rate 2-3%, surface moisture content 3-4%; 2.7 parts of HQ-HPC polycarboxylate high-performance water-reducing agent produced by Hangzhou Shibao Building Materials Technology Co., Ltd. 1 part of industrial-grade β-cyclodextrin; 210 portions of water.

[0029] The preparation method includes the following steps: a. Thoroughly stir Class F II fly ash, β-cyclodextrin, and 10% water, then add copper-plated microfiber steel fibers to obtain mixture A; b. Add S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly. c. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; d. Add crushed stone with a particle size range of 5-15mm, mixture A, and another 40% of water to the mixing drum and continue to mix thoroughly; e. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0030] Example 5 A low-cost C80 concrete is made from the following raw materials in parts by weight: 730 parts of P.O42.5 ordinary Portland cement produced by Lanxi Chaofeng Cement Co., Ltd., a subsidiary of Hongshi Holding Group; 28 samples of Class F, Grade II fly ash, with the following specifications: loss on ignition 1-3%, fineness 10-20%, 28-day activity index 75-80%, and density 2-2.5 g / cm³. 3 ; 75 parts of S95 slag powder from Hebei Anfeng Iron and Steel Group Co., Ltd., with a density of 2.85-3.05 g / cm³. 3 Specific surface area 415-440m² 2 / kg, flowability ratio 100-110%, 28-day activity index 98-103%; Zhejiang Born Metal Products Co., Ltd. produces 94.2 parts of copper-plated microfiber steel, with the following specifications: tensile strength 2500-3000MPa, length 10-13mm, equivalent diameter 0.15-0.25mm, and aspect ratio 40-85. 790 parts of crushed stone with a particle size range of 5-15mm, with the following specifications: 5-10% by mass of needle-like and flaky particles, and 2500-2650 kg / m³ saturated surface-dry apparent density. 3 Saturated surface dry water absorption rate 2-3%, particle size less than 5mm mass percentage 1.8-2.2%, particle size less than 10mm mass percentage 5.5-6.5%, crushing index 9-12%; Fineness modulus 2.4-2.8, 525 parts of sand, with the following index: mass percentage of particles smaller than 75 micrometers (stone powder content) 6-8%, saturated surface-dry apparent density 2500-2650 kg / m³. 3 Saturated surface dry water absorption rate 2-3%, surface moisture content 3-4%; 2.7 parts of HQ-HPC polycarboxylate high-performance water-reducing agent produced by Hangzhou Shibao Building Materials Technology Co., Ltd. Two parts of industrial-grade β-cyclodextrin; 240 portions of water.

[0031] The preparation method includes the following steps: a. Thoroughly stir Class F II fly ash, β-cyclodextrin, and 10% water, then add copper-plated microfiber steel fibers to obtain mixture A; b. Add S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly. c. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; d. Add crushed stone with a particle size range of 5-15mm, mixture A, and another 40% of water to the mixing drum and continue to mix thoroughly; e. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0032] Comparative Example 1 The preparation method is the same as in Example 1. The raw materials are as follows by weight: 730 parts of P.O42.5 ordinary silicate cement, 37 parts of Class II fly ash (F), 61 parts of S95 slag powder, 94.2 parts of copper-plated microfiber steel, 757 parts of crushed stone with a particle size range of 5-15mm, 522 parts of sand with a fineness modulus of 2.4-2.8, 4.388 parts of polycarboxylate high-performance water-reducing agent, and 217 parts of water.

[0033] Comparative Example 2 The preparation method is the same as in Example 1. The raw materials are as follows by weight: 730 parts of P.O42.5 ordinary silicate cement, 17 parts of Class II fly ash (F), 85 parts of S95 slag powder, 94.2 parts of copper-plated microfiber steel, 757 parts of crushed stone with a particle size range of 5-15mm, 522 parts of sand with a fineness modulus of 2.4-2.8, 4.388 parts of polycarboxylate high-performance water-reducing agent, and 217 parts of water.

[0034] Comparative Example 3 The preparation method is the same as in Example 1. The raw materials are: 730 parts by weight of P.O42.5 ordinary Portland cement, 27 parts by weight of Class II fly ash (F), 71 parts by weight of S95 slag powder, 757 parts by weight of crushed stone with a particle size range of 5-15mm, 522 parts by weight of sand with a fineness modulus of 2.4-2.8, 4.388 parts by weight of polycarboxylate high-performance water-reducing agent, and 217 parts by weight of water.

[0035] Comparative Example 4 The preparation method is the same as in Example 1. The raw materials are: 730 parts by weight of P.O42.5 ordinary silicate cement, 71 parts of S95 slag powder, 94.2 parts of copper-plated microfiber steel, 757 parts of crushed stone with a particle size range of 5-15mm, 522 parts of sand with a fineness modulus of 2.4-2.8, 4.388 parts of polycarboxylate high-performance water-reducing agent, and 217 parts of water.

[0036] Comparative Example 5 The weight and quantity of raw materials are the same as in Example 4, and the preparation method includes the following steps: a. Add Class F Grade II fly ash, S95 slag powder, β-cyclodextrin, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly; b. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add crushed stone with a particle size range of 5-15mm, copper-plated micro-wire steel fiber and another 50% of water to the mixing drum and continue to mix thoroughly. d. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0037] Comparative Example 6 The weight and quantity of raw materials are the same as in Example 5, and the preparation method includes the following steps: a. Add Class F Grade II fly ash, S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly; b. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add crushed stone with a particle size range of 5-15mm, β-cyclodextrin, copper-plated microfiber steel fibers and another 50% of water to the mixing drum and continue to mix thoroughly. d. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

[0038] Test methods: Refer to SL / T352-2020 "Test Procedures for Hydraulic Concrete" for the following tests: slump test of concrete mix, uniformity test of concrete mix, compressive strength test of concrete cube, splitting tensile strength test of concrete, drying shrinkage (wet expansion) test of concrete, abrasion resistance test of concrete (underwater steel ball method), and impermeability test of concrete (gradual pressure method). Examples 1-5 and comparative examples 1-6 are shown in Table 1.

[0039] Table 1. Concrete test data for different groups Compared to Example 1, Comparative Example 1 showed an increased proportion of Class II F fly ash and a decreased proportion of S95 slag powder. Comparative Example 2, compared to Example 1, showed a decreased proportion of Class II F fly ash and an increased proportion of S95 slag powder. Compared to Example 1, Comparative Examples 1 and 2 exhibited decreased splitting tensile strength, compressive strength, and impermeability grade. This is because the changes in proportions transformed free calcium oxide into a more stable mineral phase, preventing the free calcium oxide from reaching an optimal equilibrium. This, in turn, affected the internal structure of the concrete and its ability to fill concrete pores, thus impacting impermeability and durability.

[0040] Compared to Example 1, Comparative Example 3, without the addition of copper-plated microfiber steel fibers, showed a significant decrease in compressive strength, impact abrasion resistance, and especially splitting tensile strength. This is because the steel fibers effectively inhibit the propagation of microcracks within the concrete, thereby significantly enhancing the material's toughness and crack resistance.

[0041] Compared to Example 1, Comparative Example 4 did not add Grade II fly ash, but only added S95 slag powder. The impermeability grade and splitting tensile strength were also reduced. This is because the lack of Grade II fly ash prevented the optimal filling of concrete pores, reduced the bond strength between steel fibers and the matrix, and affected the internal structure of the concrete, thus impacting impermeability grade, splitting tensile strength, and other indicators.

[0042] Compared with Example 4, Comparative Example 5 and Comparative Example 6 differed from Example 5 in that the order of ingredient addition changed, affecting properties such as splitting tensile strength and compressive strength. This is because β-cyclodextrin reduced the treatment effect on fly ash, affecting the dispersion of fly ash and consequently the homogeneity of concrete particles, thus impacting properties such as splitting tensile strength and compressive strength.

[0043] This invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this invention, and all such changes should be included within the protection scope of this invention.

Claims

1. A low-cost C80 concrete, characterized in that: The components include the following parts by weight: P.O42.5 ordinary Portland cement: 730 parts, Class II fly ash (F grade): 27-28 parts, S95 slag powder: 71-75 parts, copper-plated microfiber steel: 78.5-94.2 parts, crushed stone with a particle size range of 5-15mm: 739-790 parts, sand with a fineness modulus of 2.4-2.8: 520-525 parts, polycarboxylate high-performance water-reducing agent: 2.7-4.8 parts, and water: 210-240 parts.

2. The low-cost C80 concrete according to claim 1, characterized in that: The components include the following parts by weight: P.O42.5 ordinary Portland cement: 730 parts, Class F II fly ash: 27 parts, S95 slag powder: 71 parts, copper-plated microfiber steel: 94.2 parts, crushed stone with a particle size range of 5-15mm: 757 parts, sand with a fineness modulus of 2.4-2.8: 522 parts, polycarboxylate high-performance water-reducing agent: 4.388 parts, and water: 217 parts.

3. A low-cost C80 concrete, characterized in that: The components include the following parts by weight: P.O42.5 ordinary Portland cement: 730 parts, Class F II fly ash: 27-28 parts, S95 slag powder: 71-75 parts, copper-plated microfiber steel: 78.5-94.2 parts, crushed stone with a particle size range of 5-15mm: 739-790 parts, sand with a fineness modulus of 2.4-2.8: 520-525 parts, polycarboxylate high-performance water-reducing agent: 2.7-4.8 parts, β-cyclodextrin: 1-2 parts, and water: 210-240 parts.

4. A low-cost C80 concrete according to claim 2 or 3, characterized in that: The Class F, Grade II fly ash has a loss on ignition of 1-3%, a fineness of 10-20%, a 28-day activity index of 75-80%, and a density of 2-2.5 g / cm³. 3 .

5. A low-cost C80 concrete according to claim 2 or 3, characterized in that: The density of the S95 slag powder is 2.85-3.05 g / cm³. 3 Specific surface area is 415-440 m² 2 / kg, with a flowability ratio of 100-110% and a 28-day activity index of 98-103%.

6. A low-cost C80 concrete according to claim 2 or 3, characterized in that: The copper-plated microfiber steel fiber has a tensile strength of 2500-3000MPa, a length of 10-13mm, an equivalent diameter of 0.15-0.25mm, and an aspect ratio of 40-85.

7. A low-cost C80 concrete according to claim 2 or 3, characterized in that: The crushed stone with a particle size range of 5-15 mm has a needle-like and flaky particle mass percentage of 5-10% and a saturated surface-dry apparent density of 2500-2650 kg / m³. 3 The saturated surface dry water absorption rate is 2-3%, the mass percentage of particles smaller than 10mm is 5.5-6.5%, and the crushing index is 9-12%.

8. A low-cost C80 concrete according to claim 2 or 3, characterized in that: The fineness modulus of the sand is 2.4-2.8, with a particle size of less than 75 micrometers accounting for 6-8% of the total mass, and a saturated surface-dry apparent density of 2500-2650 kg / m³. 3 The saturated surface dry water absorption rate is 2-3%, and the surface moisture content is 3-4%.

9. A method for preparing low-cost C80 concrete as described in any one of claims 1 or 2, characterized in that: Includes the following steps: a. Add Class F Grade II fly ash, S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly; b. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; c. Add crushed stone with a particle size range of 5-15mm, copper-plated micro-wire steel fiber and another 50% of water to the mixing drum and continue to mix thoroughly. d. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

10. A method for preparing low-cost C80 concrete as described in claim 3, characterized in that: Includes the following steps: a. Mix Class F II fly ash, β-cyclodextrin, and 10% water thoroughly; then add the specified weight proportions of copper-plated microfiber steel fibers to obtain mixture A; b. Add S95 slag powder, sand with a fineness modulus of 2.4-2.8, and 50% water to the mixing drum and mix thoroughly. c. Add P.O42.5 ordinary Portland cement to the mixing drum and continue to mix thoroughly; d. Add crushed stone with a particle size range of 5-15mm, mixture A, and another 40% of water to the mixing drum and continue to mix thoroughly; e. Add the polycarboxylate high-performance water-reducing agent to the mixing drum and continue to mix thoroughly before discharging.

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