Mechanism sand concrete and preparation method and application thereof

Abstract

The application discloses a machine-made sand concrete and a preparation method and application thereof, and comprises the following components in parts by weight: cement 350-370 parts, fly ash 50-100 parts, mineral powder 100-150 parts, microbead 40-60 parts, sand 700-820 parts, broken stone 1000-1200 parts, additive 12-16 parts and water 140-150 parts. The application prepares a C80 concrete with low yield stress through the adjustment of raw materials, and uses yield stress, plastic viscosity and other indexes as the basis of pumping performance, and uses extension degree and reverse slump time as auxiliary indexes, so as to reduce pumping pressure and improve pumping efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, in particular to a machine-made sand concrete and a preparation method and application thereof. BACKGROUND

[0002] C80 concrete belongs to the category of ultra-high strength concrete and is widely used in super high-rise projects. Due to its low water-binder ratio (below 0.26) and high amount of cementitious materials (600 kg / m 3 The above problems affect the pumping of concrete. The super high-rise project often involves super high pumping, long pumping distance and high pumping height, which causes the pumping pressure to exceed the bearing range of existing equipment, resulting in very limited pumping output, and pumping accidents such as pipe blockage and pipe explosion.

[0003] Therefore, it is urgent to develop a machine-made sand concrete to reduce the pumping pressure and improve the pumping efficiency. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application prepares a C80 concrete with low yield stress by adjusting the raw materials, uses yield stress, plastic viscosity and other indicators as the basis of pumping performance, and uses extension degree and reverse slump time as auxiliary indicators to reduce the pumping pressure and improve the pumping efficiency.

[0005] According to a first aspect of the present application, a machine-made sand concrete is provided, which comprises the following components in parts by weight: cement 350-370 parts, fly ash 50-100 parts, mineral powder 100-150 parts, microbeads 40-60 parts, sand 700-820 parts, gravel 1000-1200 parts, additive 12-16 parts and water 140-150 parts.

[0006] According to some embodiments of the present application, the preparation raw materials of the concrete further comprise water.

[0007] According to some embodiments of the present application, the preparation raw materials of the concrete comprise the following components in parts by weight: cement 350-370 parts, fly ash 50-100 parts, mineral powder 100-150 parts, microbeads 40-60 parts, sand 700-820 parts, gravel 1000-1200 parts, additive 12-16 parts and water 140-150 parts.

[0008] According to some embodiments of the present application, the additive comprises modified polyoxyethylene stearyl alcohol, polycarboxylate superplasticizer, slow-release polycarboxylate superplasticizer, retarder, micro-foaming agent, polyether modified organic silicon defoaming agent and organic lubricant.

[0009] According to some embodiments of the present application, the raw materials for preparing the modified polyoxyethylene stearyl alcohol include n-butene, acrylic acid and polyoxyethylene stearyl alcohol.

[0010] According to some embodiments of the present application, the method for preparing the modified polyoxyethylene stearyl alcohol includes mixing the n-butene, the acrylic acid and the polyoxyethylene stearyl alcohol under the action of a catalyst.

[0011] Under the above conditions, the polyoxyethylene stearyl alcohol, the n-butene and the acrylic acid are subjected to a copolymerization reaction. During the reaction, the hydrophobic groups introduced by the n-butene and the hydrophilic groups introduced by the acrylic acid are copolymerized with the polyoxyethylene stearyl alcohol molecules to form a copolymer having hydrophobic groups and hydrophilic groups, which can form a hydrophilic layer on the surface of cement particles and a hydrophobic layer on the surface of concrete, effectively coat the particles such as sand and aggregate, and does not affect the hydration reaction of the cement particles, further improves the durability and impermeability of the concrete, and thus prolongs the service life of the concrete structure.

[0012] According to some embodiments of the present application, the additive includes 10-20 parts of the modified polyoxyethylene stearyl alcohol, 20-30 parts of a polycarboxylate superplasticizer, 10-20 parts of a polycarboxylate superplasticizer, 4-5 parts of a retarder, 0.03-0.2 parts of a micro-foaming agent, 0.05-0.4 parts of a polyether modified silicone defoaming agent, 0.02-0.1 parts of an organic lubricant, and 30-50 parts of water.

[0013] According to some embodiments of the present application, the cement is P.O42.5 Portland cement.

[0014] According to some embodiments of the present application, the 28d compressive strength of the cement is not less than 50 MPa.

[0015] According to some embodiments of the present application, the mineral powder includes S95 grade mineral powder.

[0016] According to some embodiments of the present application, the fly ash includes grade II fly ash.

[0017] According to some embodiments of the present application, the microbead is a global type microbead with a particle size distribution of 0.1-5 um.

[0018] According to some embodiments of the present application, the sand is limestone machine-made sand with a powder content of 5-10%.

[0019] The above sand index meets the requirements of the national standard for type II sand, and the MB value is within 1.4.

[0020] According to some embodiments of the present application, the crushed stone is limestone crushed stone with a particle size of 5-16 mm.

[0021] The above crushed stone meets the requirements of the national standard for type II stone.

[0022] The present application adopts ordinary portland cement, machine-made sand and limestone, does not mix steel fibers, reduces the cement consumption, effectively reduces the cost, and reduces carbon emissions; the present application uses yield stress and plastic viscosity to represent the fluidity and flowability of the concrete, which is more in line with the characteristics of the concrete flowing in the pipeline, and is more instructive.

[0023] In the present application, the microbeads in the raw material system in the above-mentioned proportion can greatly reduce the plastic viscosity and yield stress of the concrete without reducing the strength of the concrete; the 5-10% powder in the machine-made sand effectively supplements the glue material system, reduces the actual water-binder ratio, and ensures the strength of the matrix without mixing silica fume and steel fibers; the multifunctional additive is used to reduce the viscosity, suppress the bubble, defoam and introduce fine small bubbles, and the synergistic effect of various technical means effectively reduces the bubble pore size and plastic viscosity of the C80 concrete; the yield stress is used as an evaluation index of the pumping of the C80 concrete, which more truly reflects the pumping performance.

[0024] According to the embodiment of the second aspect of the present application, a preparation method of concrete is provided, comprising the following steps:

[0025] S1. Mixing cement, fly ash, mineral powder and microbeads to obtain a cementing slurry;

[0026] S2. Adding sand and gravel into the cementing slurry to obtain a mixture;

[0027] S3. Mixing the dispersing additive with the mixture.

[0028] In the present application, the gelled slurry is fully wrapped on the surface of sand and gravel, which improves the structure of the concrete interfacial transition zone and is conducive to improving the strength of the concrete. The microbeads can effectively disperse and reduce the yield stress of the concrete slurry, thereby reducing the pumping pressure of the concrete. Specifically, the modified polyoxyethylene stearyl alcohol in the additive has hydrophilicity, which promotes better compatibility with the cement slurry, thereby fully coating the surface of sand and gravel and improving the structure of the concrete interfacial transition zone; the introduction of the modified polyoxyethylene stearyl alcohol improves the bonding performance of the cement particles and sand and gravel, increases the cohesion and shear strength of the concrete, and further improves the strength of the concrete; through suitable carboxylation modification, the inhibitory effect of the modified polyoxyethylene stearyl alcohol on the cement particles is reduced, so that the cement particles can still perform normal hydration reaction and maintain the strength development of the concrete. The friction between the concrete particles and the cement slurry is the main cause of resistance. The addition of the modified polyoxyethylene stearyl alcohol can improve the wettability and dispersibility between the concrete particles and the cement slurry, thereby reducing the friction and adhesion between the particles, making the concrete more easily flow and pump. The hydrophobic group and hydrophilic group copolymer polyoxyethylene stearyl alcohol is a molecule composed of a hydrophobic group and a hydrophilic group, and the hydrophobic group can be adsorbed on the surface of the concrete particles to form a covering layer, thereby reducing the adhesion between the particles; at the same time, the hydrophilic group can be adsorbed in the surrounding cement slurry to form a lubricating layer, thereby reducing the friction between the concrete particles and the cement slurry, thereby reducing the internal friction coefficient and viscous resistance of the concrete, making the concrete more easily flow and pump, thereby reducing the pumping pressure and improving the pumping efficiency.

[0029] According to some embodiments of the present application, the mixing time in step S1 is 30-40s.

[0030] According to some embodiments of the present application, the mixing time in step S2 is 30-40s.

[0031] According to some embodiments of the present application, the mixing time in step S3 is 50-60s.

[0032] According to some embodiments of the third aspect of the present application, a use of the concrete in the field of construction is provided. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0034] In the present application, the term "and / or", describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects.

[0035] It should be understood that the size of the sequence number of the above processes in various embodiments of the present application does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence, and the execution order of the processes should be determined according to their functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0036] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0037] The weight of the related components mentioned in the specification of the embodiments of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of each component, therefore, as long as the content of the related components in the specification of the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass mentioned in the specification of the embodiments of the present application can be μg, mg, g, kg and other mass units commonly known in the chemical field.

[0038] The preparation method of the modified polyoxyethylene stearyl alcohol in the embodiment is: 100 parts of polyoxyethylene stearyl alcohol, 5 parts of acrylic acid, 10 parts of n-butene and a catalyst benzoyl peroxide are mixed at 80℃ for 4h to obtain the modified polyoxyethylene stearyl alcohol.

[0039] Embodiment 1:

[0040] The present embodiment provides a low yield stress C80 concrete and a preparation method thereof, the preparation method is:

[0041] A1. Mix the cement, fly ash, mineral powder and microbeads uniformly, add half of the water, and stir for 30s to obtain a cementitious slurry;

[0042] A2. Add sand and gravel to the cementitious slurry, stir for 30s to obtain a mixture;

[0043] A3. Mix the water reducing agent and the other part of the water uniformly to obtain an admixture solution;

[0044] A4. Stir the admixture solution and the mixture for 60s to obtain the low yield stress C80 concrete.

[0045] In the preparation method, by weight parts, including: cement 350 parts, fly ash 75 parts, slag 150 parts, microbeads 50 parts, sand 800 parts, gravel 860 parts, water 140 parts, additive 14 parts. The mass percentage of each component of the additive is: modified polyoxyethylene stearyl alcohol 10%, small molecular weight polycarboxylate superplasticizer 25%, slow-release polycarboxylate superplasticizer 15%, sodium gluconate 4%, micro-foaming agent 0.08%, polyether modified silicone defoamer 0.27%, organic lubricant 0.05%, water 44.8%.

[0046] Example 2

[0047] The embodiment provides a low yield stress C80 concrete and a preparation method thereof, and the preparation method is that;

[0048] A1. uniformly mix cement, fly ash, slag and microbeads, add half of water, and stir for 30s to obtain a cementing slurry;

[0049] A2. add sand and gravel into the cementing slurry, and stir for 30s to obtain a mixture;

[0050] A3. uniformly mix a water reducing agent and the other part of water to obtain an additive solution;

[0051] A4. stir the additive solution and the mixture for 60s to obtain the low yield stress C80 concrete.

[0052] In the preparation method, by weight parts, including: cement 370 parts, fly ash 100 parts, slag 100 parts, microbeads 40 parts, sand 800 parts, gravel 850 parts, water 140 parts, additive 13 parts. The mass percentage of each component of the additive is: modified polyoxyethylene stearyl alcohol 10%, small molecular weight polycarboxylate superplasticizer 30%, slow-release polycarboxylate superplasticizer 20%, sodium gluconate 4%, micro-foaming agent 0.08%, polyether modified silicone defoamer 0.25%, organic lubricant 0.07%, water 35%.

[0053] Example 3

[0054] The embodiment provides a low yield stress C80 concrete and a preparation method thereof, and the preparation method is that;

[0055] A1. uniformly mix cement, fly ash, slag and microbeads, add half of water, and stir for 30s to obtain a cementing slurry;

[0056] A2. add sand and gravel into the cementing slurry, and stir for 30s to obtain a mixture;

[0057] A3. uniformly mix a water reducing agent and the other part of water to obtain an additive solution;

[0058] A4. The admixture solution is stirred with the mixture for 60 seconds to obtain a low yield stress C80 concrete.

[0059] In the preparation method, by weight fraction, it comprises: cement 370 parts, fly ash 50 parts, slag 150 parts, microbead 60 parts, sand 820 parts, gravel 840 parts, water 150 parts, admixture 14 parts. The mass percentage of each component of the admixture is: modified polyoxyethylene stearyl alcohol 10%, small molecular weight polycarboxylate superplasticizer 25%, slow-release polycarboxylate superplasticizer 20%, sodium gluconate 4%, micro-foaming agent 0.08%, polyether modified silicone defoamer 0.25%, organic lubricant 0.05%, water 40.2%.

[0060] Comparative Example 1

[0061] This comparative example provides a low yield stress C80 concrete and a preparation method thereof. The difference between this comparative example and Example 1 is that the amount of microbead added is 30 parts, and the other conditions are the same.

[0062] Comparative Example 2

[0063] This comparative example provides a low yield stress C80 concrete and a preparation method thereof. The difference between this comparative example and Example 1 is that the modified polyoxyethylene stearyl alcohol is not included, and the other conditions are the same.

[0064] Comparative Example 3

[0065] This comparative example provides a low yield stress C80 concrete and a preparation method thereof. The difference between this comparative example and Example 1 is that n-butene is not added in the modified polyoxyethylene stearyl alcohol, and the other conditions are the same.

[0066] Test Example 1

[0067] The C80 concrete prepared in the above examples and comparative examples is subjected to performance test, and the test data is shown in Table 1 (where the pump model is CB5143CB0408 produced by Sany Heavy Industry, the displacement is uniformly 60%, and the pumping height is within 100 meters).

[0068] Table 1. Performance test

[0069]

[0070]

[0071] From Table 1, it can be seen that by collocation of components, under synergistic effect, the plastic viscosity and yield stress of the concrete can be greatly reduced without reducing the strength of the concrete, which is beneficial to improve the fluidity and pumping performance of the concrete, making it easier to construction and processing. By adding the modified polyoxyethylene stearyl alcohol, the wettability and dispersibility between the concrete particles and the cement paste can be improved, thereby reducing the friction and adhesion between the particles, making the concrete more easily flow and pump. The hydrophobic group and hydrophilic group copolymer polyoxyethylene stearyl alcohol is a molecule composed of hydrophobic group and hydrophilic group, the hydrophobic group can be adsorbed on the surface of the concrete particles, forming a covering layer, thereby reducing the adhesion between the particles; at the same time, the hydrophilic group can be adsorbed in the surrounding cement paste, forming a lubricating layer, thereby reducing the friction between the concrete particles and the cement paste, thereby reducing the internal friction coefficient and viscous resistance of the concrete, making the concrete more easily flow and pump, thereby reducing the pumping pressure and improving the pumping efficiency.

[0072] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement 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 concrete, characterized by, The components include cement 350-370 parts, fly ash 50-100 parts, mineral powder 100-150 parts, microbead 40-60 parts, sand 700-820 parts, crushed stone 1000-1200 parts, additive 12-16 parts and water 140-150 parts by weight; The additive comprises modified polyoxyethylene stearyl alcohol, polycarboxylate superplasticizer, slow-release polycarboxylate superplasticizer, retarder, micro-foaming agent, polyether modified silicone defoamer and organic lubricant. The raw materials for preparing the modified polyoxyethylene stearyl alcohol include n-butene, acrylic acid and polyoxyethylene stearyl alcohol.

2. The concrete according to claim 1, characterized in that The microbead is a global type microbead with a particle size distribution of 0.1-5 μm.

3. The concrete according to claim 1, characterized in that, The sand is lime stone machine-made sand with a powder content of 5-10%.

4. The concrete according to claim 1, characterized in that, The crushed stone is lime stone crushed stone with a particle size of 5-16 mm.

5. Application of the machine-made sand concrete according to any one of claims 1-4 in the field of construction.

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