Mechanism sand self-compacting high-strength concrete with internal curing effect

Abstract

The application belongs to the field of building materials, and particularly relates to a machine-made sand self-compacting high-strength concrete with internal curing effect, which comprises the following components in parts by weight: 450-500 parts of cement, 45-75 parts of silica fume, 25-50 parts of fly ash beads, 25-50 parts of machine-made sand stone powder, 750-860 parts of zeolite powder modified machine-made sand, 900-1050 parts of gravel, 5.5-6.5 parts of water reducing agent, and 200-230 parts of water. The zeolite powder modified machine-made sand is used to coat the surface of the machine-made sand, so that the roughness of the surface of the machine-made sand is improved, the roundness of the machine-made sand is improved, the working performance of the machine-made sand self-compacting high-strength concrete is effectively improved, a large number of gaps and channels exist in the zeolite powder, a part of free water is absorbed in the initial stage of stirring, the part of water is discharged in the hardening process of the concrete, participates in the hydration reaction, plays the role of an internal curing agent, and effectively reduces the shrinkage of the machine-made sand self-compacting high-strength concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, in particular to a machine-made sand self-compacting high-strength concrete with internal curing effect. BACKGROUND

[0002] As the largest artificial building material today, the fine aggregate used in the preparation process of concrete is usually natural river sand. However, with the overexploitation of natural river sand, it is facing a problem of resource shortage. Current researches have shown that it is feasible to use machine-made sand to replace natural river sand to prepare concrete. However, due to the irregular shape, poor particle shape roundness, high surface roughness of machine-made sand, and the presence of stone powder in machine-made sand, the workability and mechanical properties of machine-made sand concrete are poor.

[0003] High-strength concrete refers to concrete with a strength grade of C60 and above. Due to its high compressive strength, strong deformation resistance, large density, and low porosity, high-strength concrete is widely used in high-rise building structures, large-span bridge structures, and some special structures. The biggest feature of high-strength concrete is its high compressive strength, which is generally 4-6 times that of ordinary strength concrete, so the cross section of the component can be reduced, and therefore it is most suitable for high-rise buildings. Tests have shown that under certain axial compression ratio and appropriate stirrup ratio, high-strength concrete frame columns have good seismic performance. Moreover, the column cross-sectional size is reduced, the self-weight is reduced, short columns are avoided, which is beneficial to the seismic performance of the structure, and the economic benefits are improved.

[0004] However, compared with ordinary concrete, the amount of high-strength concrete binder is relatively high, which leads to relatively large shrinkage. Self-compacting high-strength concrete has greater flowability, which can exacerbate shrinkage. Therefore, it is of great significance to develop a machine-made sand self-compacting high-strength concrete with small shrinkage, large flowability, and high strength. SUMMARY

[0005] The purpose of the present application is to provide a machine-made sand self-compacting high-strength concrete with internal curing effect to solve the above problems.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] The machine-made sand self-compacting high-strength concrete with internal curing effect comprises the following components by weight: 450-500 parts of cement, 45-75 parts of silica fume, 25-50 parts of fly ash beads, 25-50 parts of machine-made sand stone powder, 750-860 parts of zeolite powder modified machine-made sand, 900-1050 parts of crushed stone, 5.5-6.5 parts of water reducing agent, and 200-230 parts of water.

[0008] Further, the zeolite powder modified machine-made sand is prepared by the following method:

[0009] Step 1, mix the zeolite powder with water in a mass ratio of (15-20):1 to prepare a zeolite powder slurry;

[0010] Step 2, add cement to the zeolite powder slurry, stir until uniform, then add machine-made sand, soak and stir for 15-30 min, and then take out and dry to obtain zeolite powder modified machine-made sand, wherein the amount of cement added is 0.5-1 wt% of the amount of zeolite powder.

[0011] Further, the drying temperature of the drying is not more than 65℃.

[0012] Further, the particle size of the zeolite powder is 200 mesh.

[0013] Further, the fineness modulus of the machine-made sand is 2.7-3.0.

[0014] Further, the machine-made sand powder is a 325 mesh machine-made sand powder obtained by ball milling a raw machine-made sand powder.

[0015] Further, the cement is P·O ordinary portland cement.

[0016] Further, the crushed stone is 5-20 mm continuous gradation basalt crushed stone.

[0017] Further, the water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent with a water reducing rate of more than 25%.

[0018] The beneficial effects of the present application are:

[0019] 1. The zeolite powder modified machine-made sand of the present application coats the zeolite powder on the surface of the machine-made sand, which can improve the surface roughness of the machine-made sand and improve the roundness of the machine-made sand, effectively improving the workability of the machine-made sand self-compacting high-strength concrete, and on the other hand, the zeolite powder has a large number of voids and channels inside, which can absorb a part of the free water at the beginning of stirring, and during the hardening process of the concrete, this part of water is discharged and participates in the hydration reaction, playing the role of internal curing agent, effectively reducing the shrinkage of the machine-made sand self-compacting high-strength concrete, and the addition of a small amount of cement to the zeolite powder slurry can make the zeolite powder play the role of internal curing agent while appropriately reducing its influence on the consistency of the slurry, and the addition of a small amount of cement can effectively increase the bonding strength of the zeolite powder slurry and the machine-made sand and improve the coating effect of the machine-made sand.

[0020] 2. This invention uses the theory of closest packing to rationally design the proportion of each raw material from the perspective of raw material particle size and activity. The manufactured sand and gravel powder is finely ground and added as filler to the manufactured sand self-compacting high-strength concrete system. On the one hand, it can effectively improve the density of the obtained concrete and increase its strength. On the other hand, the finely ground manufactured sand and gravel powder can act as crystal nuclei for cement hydration, accelerate cement hydration, and give it higher early mechanical properties. Detailed Implementation

[0021] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0022] Example 1

[0023] Self-compacting high-strength concrete with internal curing properties made from manufactured sand comprises the following components by weight:

[0024] Cement: 450 parts, silica fume: 75 parts, fly ash microspheres: 40 parts, manufactured sand and gravel powder: 25 parts, zeolite powder modified manufactured sand: 860 parts, crushed stone: 900 parts, water-reducing agent: 5.5 parts, water: 230 parts.

[0025] Zeolite powder modified manufactured sand is prepared by the following method:

[0026] Zeolite powder and water are mixed at a water-to-material ratio of 15:1 to prepare a zeolite powder slurry, wherein the particle size of the zeolite powder is 200 mesh.

[0027] Cement is added to the zeolite powder slurry and stirred evenly. Then, manufactured sand with a fineness modulus of 2.7 is added and stirred while soaking for 15-30 minutes. The mixture is then removed and dried at 50-65℃ to obtain zeolite powder modified manufactured sand. The amount of cement added is 0.5% of the amount of zeolite powder and manufactured sand.

[0028] In this embodiment, the manufactured sand and gravel powder is undisturbed manufactured sand and gravel powder with a particle size of 325 mesh obtained by ball milling; the cement is P·O42.5 ordinary Portland cement; the crushed stone is 5-20mm continuously graded basalt crushed stone; and the water-reducing agent is powdered high-performance polycarboxylate water-reducing agent with a water reduction rate of 27%.

[0029] Example 2

[0030] Self-compacting high-strength concrete with internal curing properties made from manufactured sand comprises the following components by weight:

[0031] Cement: 450 parts, silica fume: 75 parts, fly ash microspheres: 40 parts, manufactured sand and gravel powder: 50 parts, zeolite powder modified manufactured sand: 860 parts, crushed stone: 900 parts, water-reducing agent: 6.5 parts, water: 230 parts.

[0032] The zeolite powder modified machine-made sand is prepared by the following method:

[0033] The zeolite powder is mixed with water in a water-material ratio of 15:1 to prepare a zeolite powder slurry, wherein the particle size of the zeolite powder is 200 mesh;

[0034] Cement is added to the zeolite powder slurry, and after uniform stirring, machine-made sand with a fineness modulus of 2.7 is added. The machine-made sand is soaked and stirred for 15-30 minutes, taken out and dried at 50-65°C to obtain the zeolite powder modified machine-made sand. The addition amount of cement is 0.5% of the amount of zeolite powder and 0.5% of the machine-made sand.

[0035] In this embodiment, the machine-made sand stone powder is the original machine-made sand stone powder, and the particle size of the machine-made sand stone powder obtained after ball milling treatment is 325 mesh. The cement is P·O42.5 ordinary portland cement. The crushed stone is 5-20 mm continuously graded basalt crushed stone. The water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is 27%.

[0036] Example 3

[0037] The machine-made sand self-compacting high-strength concrete with internal curing effect comprises the following components in parts by weight:

[0038] Cement: 500 parts, silica fume: 50 parts, fly ash microbeads: 40 parts, machine-made sand stone powder: 25 parts, zeolite powder modified machine-made sand: 750 parts, crushed stone: 1050 parts, water reducing agent: 6.5 parts, and water: 200 parts.

[0039] The zeolite powder modified machine-made sand is prepared by the following method:

[0040] The zeolite powder is mixed with water in a water-material ratio of 15:1 to prepare a zeolite powder slurry, wherein the particle size of the zeolite powder is 200 mesh;

[0041] Cement is added to the zeolite powder slurry, and after uniform stirring, machine-made sand with a fineness modulus of 2.7 is added. The machine-made sand is soaked and stirred for 15-30 minutes, taken out and dried at 50-65°C to obtain the zeolite powder modified machine-made sand. The addition amount of cement is 0.5% of the amount of zeolite powder and 0.5% of the machine-made sand.

[0042] In this embodiment, the machine-made sand stone powder is the original machine-made sand stone powder, and the particle size of the machine-made sand stone powder obtained after ball milling treatment is 325 mesh. The cement is P·O42.5 ordinary portland cement. The crushed stone is 5-20 mm continuously graded basalt crushed stone. The water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is 27%.

[0043] Example 4

[0044] The machine-made sand self-compacting high-strength concrete with internal curing effect comprises the following components in parts by weight:

[0045] Cement: 500 parts, silica fume: 50 parts, fly ash microbead: 40 parts, machine-made sandstone powder: 25 parts, zeolite powder modified machine-made sand: 750 parts, gravel: 1050 parts, water reducing agent: 6.5 parts, water: 200 parts.

[0046] The zeolite powder modified machine-made sand is prepared by the following method:

[0047] The zeolite powder is mixed with water in a water-material ratio of 20:1 to prepare a zeolite powder slurry, wherein the particle size of the zeolite powder is 200 mesh;

[0048] Cement is added to the zeolite powder slurry, and after uniform stirring, machine-made sand with a fineness modulus of 2.7 is added, and stirring is performed while soaking for 15-30 min, and then the mixture is taken out and dried at 50-65°C to obtain zeolite powder modified machine-made sand, wherein the addition amount of cement is 1% of the amount of zeolite powder and 1% of the amount of machine-made sand.

[0049] In this embodiment, the machine-made sandstone powder is the original machine-made sandstone powder treated by ball milling to obtain machine-made sandstone powder with a particle size of 325 mesh; the cement is P·O42.5 ordinary portland cement; the gravel is 5-20 mm continuous graded basalt gravel; the water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is 27%.

[0050] Example 5

[0051] The machine-made sand self-compacting high-strength concrete with internal curing effect comprises the following components in parts by weight:

[0052] Cement: 475 parts, silica fume: 60 parts, fly ash microbead: 50 parts, machine-made sandstone powder: 40 parts, zeolite powder modified machine-made sand: 800 parts, gravel: 1050 parts, water reducing agent: 6.5 parts, water: 220 parts.

[0053] The zeolite powder modified machine-made sand is prepared by the following method:

[0054] The zeolite powder is mixed with water in a water-material ratio of 20:1 to prepare a zeolite powder slurry, wherein the particle size of the zeolite powder is 200 mesh;

[0055] Cement is added to the zeolite powder slurry, and after uniform stirring, machine-made sand with a fineness modulus of 2.7 is added, and stirring is performed while soaking for 15-30 min, and then the mixture is taken out and dried at 50-65°C to obtain zeolite powder modified machine-made sand, wherein the addition amount of cement is 1% of the amount of zeolite powder and 1% of the amount of machine-made sand.

[0056] In the embodiment, the machine-made sandstone powder is a 325-mesh machine-made sandstone powder obtained by ball milling of the original machine-made sandstone powder; the cement is P·O42.5 ordinary portland cement; the crushed stone is 5-20 mm continuously-graded basalt crushed stone; the water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is 27%.

[0057] Comparative Example 1

[0058] The machine-made sand self-compacting high-strength concrete with internal curing effect comprises the following components in parts by weight:

[0059] Cement: 475 parts, silica fume: 60 parts, fly ash cenospheres: 50 parts, machine-made sandstone powder: 40 parts, machine-made sand: 800 parts, crushed stone: 1050 parts, water reducing agent: 6.5 parts, and water: 220 parts.

[0060] In the comparative example, the machine-made sandstone powder is a 325-mesh machine-made sandstone powder obtained by ball milling of the original machine-made sandstone powder; the cement is P·O42.5 ordinary portland cement; the crushed stone is 5-20 mm continuously-graded basalt crushed stone; the water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is 27%; and the fineness modulus of the machine-made sand is 2.7.

[0061] The working performance, mechanical properties and shrinkage performance of the machine-made sand self-compacting high-strength concrete with internal curing effect obtained in Examples 1-5 of the present application are tested and compared with those of Comparative Example 1, and the test results are shown in Table 1.

[0062] As shown in Table 1, the machine-made sand self-compacting high-strength concrete with internal curing effect obtained in each of the examples of the present application has excellent working performance, small slump loss, a 28d strength of about 100 MPa, and low 28d dry shrinkage, which can be as low as 305με, and each of the performances is superior to those of Comparative Example 1.

[0063] Table 1 Performance test results of the machine-made sand self-compacting high-strength concrete with internal curing effect obtained in Examples 1-5 of the present application

[0064]

[0065]

[0066] The above description is merely preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A machine-made sand high-strength concrete having an internal curing effect, characterized by, The composition comprises the following ingredients by weight: 450-500 parts of cement, 45-75 parts of silica ash, 25-50 parts of fly ash beads, 25-50 parts of machine-made sandstone powder, 750-860 parts of zeolite powder modified machine-made sand, 900-1050 parts of crushed stone, 5.5-6.5 parts of water reducing agent, 200-230 parts of water; The zeolite powder modified machine-made sand is prepared by the following method: Step 1, mix the zeolite powder with water according to a water-material ratio of (15-20):1 to prepare a zeolite powder slurry; Step 2, add cement to the zeolite powder slurry, stir uniformly, then add machine-made sand, and stir while soaking for 15-30 min, and then take out and dry to obtain the zeolite powder modified machine-made sand, wherein the addition amount of cement is 0.5-1 wt% of the amount of zeolite powder.

2. The machine-made high-strength concrete having internal curing effect according to claim 1, characterized by, The drying temperature of the drying is not more than 65℃.

3. The machine-made high-strength concrete having internal curing effect according to claim 1, characterized by, The particle size of the zeolite powder is 200 mesh.

4. The machine-made high-strength concrete having internal curing according to claim 1, characterized by, The fineness modulus of the machine-made sand is 2.7-3.

0.

5. The machine-made high-strength concrete having internal curing according to claim 1, characterized by, The machine-made sandstone powder is a 325 mesh machine-made sandstone powder obtained by ball milling of a raw machine-made sandstone powder.

6. The machine-made high-strength concrete having internal curing according to claim 1, characterized by, The cement is P·O ordinary portland cement.

7. The machine-made high-strength concrete having internal curing according to claim 1, characterized by, The crushed stone is 5-20 mm continuously graded basalt crushed stone.

8. The machine-made high-strength concrete having internal curing according to claim 1, characterized by, The water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is greater than 25%. The water reducing agent is a powdery high-performance polycarboxylic acid water reducing agent, and the water reducing rate is greater than 25%.

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