Preparation method of plastic concrete using mechanism sand grading

Abstract

The application relates to the field of plastic concrete, and particularly discloses a preparation method of plastic concrete using machine-made sand grading, which comprises the following steps: screening construction waste to obtain sand I, sand II and sand III with particle sizes >0.5 mm, 0.5-0.2 mm and <=0.2 mm; uniformly mixing sand I, a coupling agent and an emulsion, drying the mixture to obtain machine-made sand I; uniformly stirring sand II and a polyvinyl alcohol solution, adding an epoxy-based silicate, and heating to obtain machine-made sand II; uniformly mixing sand III, a calcium acetate solution and a polysulfonate resin, kneading the mixture, and then performing roasting activation to obtain machine-made sand III; uniformly mixing cement, water, machine-made sand I, machine-made sand II, machine-made sand III, gravel, an acrylic-methyl acrylic copolymer, a blending powder and an additive. The application forms grading machine-made sand through a specific modification method, and can significantly improve the elastic modulus and impermeability of the plastic concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of plastic concrete, more particularly, it relates to a preparation method of plastic concrete using machine-made sand grading. BACKGROUND

[0002] The concrete cutoff wall is an effective anti-seepage technology for treating foundation seepage and engineering risk removal. It is a continuous underground wall with anti-seepage function, which is formed by continuously drilling and grooving in loose and permeable foundation or tailings (reservoir) dam and its cofferdam, water retaining dam body, using slurry to solidify the wall, and pouring concrete under the slurry. In the construction or reinforcement of tailings (reservoir) dam and its cofferdam, water retaining dam, etc., the fillers of the building are mainly clay, silt, gravel or stone mixture, and the quality of the soil is poor. Therefore, the anti-seepage body needs to have strong deformation adaptability, otherwise, the deformation and cracking of the cutoff wall will easily occur, which will bring great safety hazards to the project. Plastic concrete is a material with mechanical properties and deformation properties between soil and ordinary concrete. The elastic modulus of plastic concrete is similar to that of the foundation, and it has greater ultimate deformation than ordinary concrete, which can well adapt to the softer foundation. Therefore, plastic concrete is mostly used for cutoff walls.

[0003] Plastic concrete is a flexible material with low cement content and mixed with more river sand, bentonite, fly ash and other materials. However, in recent years, the clay content of natural river sand has increased, and due to mining and environmental protection reasons, the price of natural river sand is increasing. At the same time, with the increasing of demolition and reconstruction, the amount of construction waste is also increasing, which brings great pressure to the environment. Therefore, it is very important to develop plastic concrete with good elasticity and excellent impermeability by comprehensively utilizing construction waste. SUMMARY

[0004] The present application provides a preparation method of plastic concrete using machine-made sand grading, which can effectively utilize construction waste, form machine-made sand grading, and improve the elastic modulus and impermeability of plastic concrete.

[0005] The preparation method of plastic concrete using machine-made sand grading provided by the present application adopts the following technical scheme:

[0006] A preparation method of plastic concrete using machine-made sand grading, comprising the following steps:

[0007] Screening the construction waste to obtain sand I, sand II and sand III with particle size > 0.5 mm, particle size 0.5-0.2 mm and particle size ≤ 0.2 mm;

[0008] Mixing and stirring the sand I, coupling agent and emulsion uniformly and drying to obtain machine-made sand I;

[0009] Sand II is stirred with polyvinyl alcohol solution, and the pH value is adjusted to be alkaline, and then epoxy silicate is added to obtain mechanism sand II by heating reaction;

[0010] Sand III, calcium acetate solution and polysulfonate resin are stirred and mixed uniformly, and then kneaded and activated by baking to obtain mechanism sand III. Cement, water, mechanism sand I, mechanism sand II, mechanism sand III, gravel, acrylic-methacrylic copolymer, admixture and additive are stirred and mixed uniformly.

[0011] Further, the building slag is composed of 5-10% of stone particles with a particle size of >3mm, 10-20% of powder particles with a particle size of 0.05-0.005mm, 3-8% of clay particles with a particle size of <0.005mm, and the rest of sand particles with a particle size of 3-0.05mm.

[0012] Further, the pH value is adjusted to 7.5-8.5 by using sodium hydroxide solution, and the reaction is carried out at 60-80℃ for 1-2h to obtain mechanism sand II.

[0013] Further, the mechanism sand III is obtained by baking and activating at a temperature of 180-220℃ for 20-30min.

[0014] Further, the epoxy silicate is trimethylsilicone epoxy silicate.

[0015] The building slag is classified and screened to form sand with different gradations as fine aggregate to fill in the concrete. Sand I is stirred and mixed uniformly with coupling agent and emulsion and dried. The coupling agent can promote the compatibility between sand I and emulsion, and the emulsion has excellent adhesion. After drying and film forming, it can be firmly combined on the surface of sand particles, improve the strength and adhesion of sand, effectively combine with other raw material components, enhance the compactness of concrete, and at the same time, endow the concrete with certain elasticity, so that the plastic concrete has certain elastic modulus and excellent impermeability.

[0016] Sand II is stirred with polyvinyl alcohol solution to endow sand II with excellent adhesion. The epoxy groups in the added epoxy silicate can react with the hydroxyl groups of polyvinyl alcohol to form products containing siloxane bonds. Sand II plays an excellent modification role, endows mechanism sand II with good water resistance, and improves its impermeability. At the same time, the alkaline environment can promote the condensation reaction and improve the modification of sand II, and also endows mechanism sand II with certain alkalinity, which is beneficial to stimulate the activity of cement, promote the hydration of cement, change the surface tension of concrete, make it more easily flow and vibrate, and improve the plasticity and workability of concrete.

[0017] The sand III, calcium acetate solution and polysulfonate resin are stirred and mixed uniformly, wherein the free calcium ions in the calcium acetate solution can react with the polysulfonate resin to promote the hardening and strength development of the concrete. The mechanism sand III after activation by baking can be well combined with the admixture, improve the microenvironment inside the concrete and improve the impermeability of the concrete. The acrylic-methacrylic acid copolymer can also form a complex with the acetate ions in the system to promote the dispersion of the cement particles, improve the utilization rate of the cement in the concrete, thereby increasing the early and long-term strength of the concrete.

[0018] Preferably, the mass ratio of the sand I, the coupling agent and the emulsion is 10:(0.05-0.1):(2-4.5).

[0019] Preferably, the mass ratio of the sand II, the polyvinyl alcohol solution and the epoxy-based silicate is 11:(6-9):(3-7).

[0020] Preferably, the mass ratio of the sand III, the calcium acetate solution and the polysulfonate resin is 7:(5-10):(1-2).

[0021] Preferably, the cement is 30-45 parts by weight, the water is 10-20 parts by weight, the mechanism sand I is 10-20 parts by weight, the mechanism sand II is 25-35 parts by weight, the mechanism sand III is 20-30 parts by weight, the gravel is 100-125 parts by weight, the acrylic-methacrylic acid copolymer is 1-2.5 parts by weight, the admixture is 9-19 parts by weight and the additive is 0.3-0.8 parts by weight.

[0022] Preferably, the emulsion includes one of an acrylic emulsion, a polyurethane emulsion and a styrene emulsion.

[0023] Further, the emulsion is preferably a styrene emulsion.

[0024] By adopting the above technical solution, the emulsion can be firmly combined on the surface of the sand particles to improve the strength and adhesion of the sand, which is more conducive to the reaction with the cement and the admixture to generate cementitious substances to fill the voids and micro-cracks inside the concrete, thereby improving the impermeability and elastic modulus of the concrete.

[0025] Preferably, the polysulfonate resin is a sodium polysulfonate resin.

[0026] By adopting the above technical solution, the sodium polysulfonate resin can promote the dispersion of the cement particles to make them more uniformly distributed in the concrete, thereby enhancing the cohesion and strength of the cement colloid. It can also react with calcium ions to form a stable composite colloid structure, so that the mechanism sand III can be filled into the micropores and cracks of the concrete as an aggregate to reduce water permeation, improve the impermeability of the concrete and make the plastic concrete have a good elastic modulus.

[0027] Preferably, the blended powder material includes at least two of fly ash, slag, silica fume, and bentonite.

[0028] By using the above technical solution, the fly ash can reduce the cement dosage, improve the workability and fluidity of the concrete, slow down the hydration reaction rate of the concrete, and delay the early and long-term shrinkage deformation of the concrete. The slag can effectively improve the compactness and strength of the concrete, reduce the heat release and temperature rise of the concrete, and reduce the shrinkage deformation of the concrete. The silica fume can increase the early strength development of the concrete, improve the impermeability of the concrete, and reduce the shrinkage deformation and cracking tendency of the concrete. The bentonite is a clay mineral with adsorption and swelling properties, which can adjust the clay content and bonding properties of the concrete, and improve the impermeability and elastic modulus of the concrete.

[0029] Preferably, the crushed stone is granite crushed stone or limestone crushed stone with a particle size of 5-25 mm.

[0030] Preferably, the admixture includes a water reducing agent and a dispersant.

[0031] Further, the water reducing agent is preferably a polycarboxylic acid water reducing agent with a water reducing rate of 20-30%, and the dispersant is preferably an epoxy fatty acid methyl ester. The selected epoxy fatty acid methyl ester can form a chemical bond with inorganic materials such as cement and blended powder material, strengthening the cohesion of the concrete material. The epoxy fatty acid methyl ester molecule contains epoxy groups, which can form strong chemical bonds with the hydroxyl or amine groups on the surface of the concrete, thereby improving the adhesion between the concrete and other materials and further improving the impermeability of the concrete.

[0032] In summary, the present application has the following beneficial effects:

[0033] 1. The present application effectively utilizes construction waste and forms a grading machine-made sand through a specific modification method, which can improve the elastic modulus and impermeability of plastic concrete. By using suitable concrete mix proportions and mixing processes, concrete materials that meet the requirements of pouring and strength quality can be obtained. The concrete using the above machine-made sand I, machine-made sand II, and machine-made sand III as fine aggregate can fully meet the production needs of concrete components. From the perspective of social benefits, especially from the perspective of environmental protection and river management, the effective utilization of construction waste will greatly reduce the demand for natural river sand in the concrete component industry, indirectly generating huge social and economic benefits, reducing enterprise costs, and the machine-made sand concrete grading technology obtained through experiments has a broad application prospect.

[0034] 2. The application classifies and screens construction slag, wherein sand I is uniformly mixed with a coupling agent and an emulsion by stirring and dried. The coupling agent can promote the compatibility between sand I and the emulsion. The emulsion has excellent adhesion. After drying and film forming, it can be firmly combined on the surface of sand particles, improve the strength and adhesion of sand, effectively combine with other raw material components, enhance the compactness of concrete and at the same time impart certain elasticity to the concrete, so that the plastic concrete has a certain elastic modulus and excellent impermeability.

[0035] 3. Sand II is uniformly stirred with polyvinyl alcohol solution to impart excellent adhesion to sand II. The epoxy groups in the added epoxy-based silicate can undergo condensation reaction with the hydroxyl groups of polyvinyl alcohol to form a product containing silicon-oxygen bond. Sand II plays an excellent modification role, imparts good water resistance to manufactured sand II and improves its impermeability. At the same time, the alkaline environment can promote the condensation reaction and improve the modification of sand II, and also impart certain alkalinity to manufactured sand II to facilitate the activation of cement, promote cement hydration, change the surface tension of concrete, make it more easily flow and vibrate, and improve the plasticity and workability of concrete.

[0036] 4. Sand III is uniformly stirred and mixed with calcium acetate solution and polysulfonate resin. The free calcium ions in the calcium acetate solution can react with the polysulfonate resin to promote the hardening and strength development of concrete. The manufactured sand III after calcination activation can be well combined with the blended powder to improve the microenvironment inside the concrete and improve the impermeability of the concrete. The acrylic acid-methyl acrylic acid copolymer can also form a complex with the acetate ions in the system to promote the dispersion of cement particles and improve the utilization rate of cement in concrete, thereby increasing the early strength and long-term strength of concrete. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flowchart of the preparation method of the plastic concrete using manufactured sand grading of the application. DETAILED DESCRIPTION

[0038] The embodiments of the application will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only for illustration of the application and should not be regarded as limiting the scope of the application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not mentioned by the manufacturer are conventional products that can be purchased on the market. The cement used is P.042.5 Portland cement, and the particle size of the blended powder is <10 μm.

[0039] EXAMPLE

[0040] Example 1

[0041] A preparation method of plastic concrete using manufactured sand grading, comprising the following steps:

[0042] The construction waste is screened to obtain sand I, sand II and sand III with particle size >0.5 mm, particle size 0.5-0.2 mm and particle size ≤0.2 mm;

[0043] The sand I is uniformly mixed with a silane coupling agent and an acrylic emulsion, and then dried to obtain the machine-made sand I; the mass ratio of the sand I, the silane coupling agent and the acrylic emulsion is 10:0.05:4.5;

[0044] The sand II is uniformly mixed with a polyvinyl alcohol solution, and then adjusted to a pH value of 7.5 by using a sodium hydroxide solution, and then heated to 80°C for 1 h after adding trimethylsilylepoxy silicate to obtain the machine-made sand II; the mass ratio of the sand II, the polyvinyl alcohol solution and the trimethylsilylepoxy silicate is 11:9:3;

[0045] The sand III, a calcium acetate solution and a polysulfonate resin are uniformly mixed and then kneaded, and then activated by calcination at a temperature of 220°C for 20 min to obtain the machine-made sand III; the mass ratio of the sand III, the calcium acetate solution and the polysulfonate resin is 7:5:1;

[0046] The cement 30 kg, water 10 kg, machine-made sand I 20 kg, machine-made sand II 25 kg, machine-made sand III 20 kg, granite gravel with a particle size of 5-25 mm 100 kg, acrylic-methyl acrylic copolymer 1 kg, admixture 9 kg and additive 0.3 kg are uniformly mixed;

[0047] The admixture is fly ash 7 kg and silica ash 2 kg;

[0048] The additive includes polycarboxylic acid water reducer 0.2 kg with a water reducing rate of 20% and epoxy fatty acid methyl ester 0.1 kg.

[0049] Example 2

[0050] A preparation method of plastic concrete using machine-made sand grading, comprising the following steps:

[0051] The construction waste is screened to obtain sand I, sand II and sand III with particle size >0.5 mm, particle size 0.5-0.2 mm and particle size ≤0.2 mm;

[0052] The sand I is uniformly mixed with a silane coupling agent and a polyurethane emulsion, and then dried to obtain the machine-made sand I; the mass ratio of the sand I, the silane coupling agent and the polyurethane emulsion is 10:0.1:2;

[0053] The sand II is uniformly mixed with a polyvinyl alcohol solution, and then adjusted to a pH value of 8.5 by using a sodium hydroxide solution, and then heated to 60°C for 2 h after adding trimethylsilylepoxy silicate to obtain the machine-made sand II; the mass ratio of the sand II, the polyvinyl alcohol solution and the trimethylsilylepoxy silicate is 11:6:7;

[0054] After stirring and mixing the sand III, calcium acetate solution, and sodium polysulfonate resin evenly, knead the mixture and calcine it at 220℃ for 20 minutes to obtain machine-made sand III; the mass ratio of sand III, calcium acetate solution, and polysulfonate resin is 7:10:2.

[0055] Mix 45kg of cement, 20kg of water, 10kg of manufactured sand I, 35kg of manufactured sand II, 30kg of manufactured sand III, 125kg of limestone crushed stone with a particle size of 5-25mm, 2.5kg of acrylic acid-methacrylic acid copolymer, 19kg of admixture powder and 0.8kg of additives evenly.

[0056] The admixture consists of 7 kg of bentonite, 2 kg of mineral powder, and 10 kg of silica fume;

[0057] The admixture is 0.8 kg of polycarboxylate superplasticizer, with a water reduction rate of 30%.

[0058] Example 3

[0059] The difference from Example 1 is that the following are added: cement 34.1 kg, water 15.6 kg, manufactured sand I 12.9 kg, manufactured sand II 27 kg, manufactured sand III 24 kg, limestone crushed stone with a particle size of 5-25 mm gradation 113.6 kg, acrylic acid-methacrylic acid copolymer 1.8 kg, admixture powder 16.8 kg and additives 0.64 kg.

[0060] The admixtures consist of 4 kg of bentonite, 6.7 kg of mineral powder, and 6.1 kg of fly ash.

[0061] The admixtures consist of 0.44 kg of polycarboxylate superplasticizer with a water reduction rate of 25% and 0.2 kg of epoxy fatty acid methyl ester;

[0062] Everything else is the same as in Example 1.

[0063] Example 4

[0064] The difference from Example 3 is that sand I is stirred and mixed evenly with silane coupling agent and styrene emulsion and then dried to obtain machine-made sand I; the mass ratio of sand I to silane coupling agent and styrene emulsion is 10:0.03:4; the rest are the same as in Example 3.

[0065] Example 5

[0066] The difference from Example 4 is that Sand II was stirred evenly with polyvinyl alcohol solution, the pH value was adjusted to 8 with sodium hydroxide solution, and then trimethylsilyl epoxy silicate was added. The mixture was heated to 75°C and reacted for 1.8 h to obtain machine-made Sand II. The mass ratio of Sand II to polyvinyl alcohol solution and trimethylsilyl epoxy silicate was 11:8.5:5. All other aspects were the same as in Example 4.

[0067] Example 6

[0068] The difference from Example 5 is that the sand III, calcium acetate solution, and polysulfonate resin are stirred and mixed uniformly, then kneaded, and activated by calcination at a temperature of 200°C for 25 min to obtain the manufactured sand III; the mass ratio of the sand III, calcium acetate solution, and polysulfonate resin is 7:8:1.5; and the rest is the same as in Example 5.

[0069] Example 7

[0070] The difference from Example 6 is that the sand I is stirred and mixed uniformly with the silane coupling agent and the polyurethane emulsion, and then dried to obtain the manufactured sand I; the mass ratio of the sand I, the silane coupling agent, and the polyurethane emulsion is 10:0.01:7; and the rest is the same as in Example 6.

[0071] Example 8

[0072] The difference from Example 6 is that the sand II is stirred with the polyvinyl alcohol solution, the pH value is adjusted to 8.5 by using a sodium hydroxide solution, and then trimethyl siloxy silicate is added and heated to 60°C for 2 h to obtain the manufactured sand II; the mass ratio of the sand II, the polyvinyl alcohol solution, and the trimethyl siloxy silicate is 11:4:9; and the rest is the same as in Example 6.

[0073] The difference from Example 6 is that the sand III, calcium acetate solution, and polysulfonate resin are stirred and mixed uniformly, then kneaded, and activated by calcination at a temperature of 220°C for 20 min to obtain the manufactured sand III; the mass ratio of the sand III, calcium acetate solution, and polysulfonate resin is 7:15:0.6; and the rest is the same as in Example 6.

[0074] Comparative Example

[0075] Comparative Example 1

[0076] The difference from Example 6 is that the manufactured sand with a fineness modulus of 2-2.8 is used to replace the manufactured sand of the present application, i.e., the manufactured sand I, the manufactured sand II, and the manufactured sand III; and the rest is the same as in Example 6.

[0077] Comparative Example 2

[0078] The difference from Example 6 is that the sand I is not treated; and the rest is the same as in Example 6.

[0079] Comparative Example 3

[0080] The difference from Example 6 is that the sand II is stirred and mixed uniformly with the polyvinyl alcohol solution and then dried to obtain the manufactured sand II; and the rest is the same as in Example 6.

[0081] Comparative Example 4

[0082] The difference from Example 6 is that the sand III, calcium acetate solution is stirred uniformly and dried to obtain machine-made sand III, and the rest is the same as Example 6.

[0083] Comparative Example 5

[0084] The difference from Example 6 is that the acrylic-methacrylic acid copolymer is not added, and the rest is the same as Example 6.

[0085] Performance detection test

[0086] The test pieces prepared in Examples 1-8 and Comparative Examples 1-5 are subjected to 28d compressive strength, 28d elastic modulus and 28d permeability coefficient determination according to the “Hydraulic Plastic Concrete Test Procedures” (DL / T5303-2013), and the results are shown in Table 1.

[0087] Table 1

[0088] 28d compressive strength / MPa 28d modulus of elasticity / MPa 28d permeability coefficient cm / s Example 1 51.1 893 12.7*10 -10 ]]> Example 2 52.8 862 11.9*10 -10 ]]> Example 3 54.2 901 10.6*10 -10 ]] Example 4 55.7 911 9.8*10 -10 ]] Example 5 57.1 934 8.5*10 -10 ]]> Example 6 58.8 947 7.7*10 -10 ]]> Example 7 56.3 920 8.3*10 -10 ]]> Example 8 53.9 907 8.7*10 -10 ]] Comparative Example 1 41.4 1512 5.6*10 -8 ]]> Comparative Example 2 48.7 1382 7.1*10 -9 ]]> Comparative Example 3 52.1 1447 9.4*10 -8 ]]> Comparative Example 4 51.6 1316 5.6*10 -9 ]]> Comparative Example 5 52.2 1204 3.9*10 -9 ]]>

[0089] In combination with Examples 1-8 and in combination with Table 1, it can be seen that, by grading and specific modification of the construction waste, without adding additional river sand and other products, the waste is effectively utilized, the environmental pressure is greatly reduced, the compressive strength of the plastic concrete obtained meets the C50 requirement, the elastic modulus is appropriate, the deformation capacity is good, the 28d permeability coefficient is low, and the impermeability of the concrete is excellent.

[0090] In combination with Example 6 and Comparative Example 1 and in combination with Table 1, it can be seen that, by simply grading the ordinary commercially available machine-made sand, the compressive strength of the plastic concrete obtained only meets the C40 requirement, the elastic modulus is too large, the concrete is brittle, the deformation capacity is not good, and the 28d permeability coefficient is significantly increased, and the impermeability is significantly decreased.

[0091] In combination with Example 6 and Comparative Example 2 and in combination with Table 1, it can be seen that, in Comparative Example 2, the sand I is not treated, the compressive strength of the plastic concrete is decreased, the brittleness is increased, and the impermeability is decreased, which is because the coupling agent can promote the compatibility between the sand I and the emulsion, the emulsion has excellent adhesion, and after drying and film forming, it can be firmly combined on the surface of the sand particles, improve the strength and adhesion of the sand, effectively combine with other raw material components, enhance the density of the concrete, and at the same time impart certain elasticity to the concrete, so that the plastic concrete has certain elastic modulus and excellent impermeability.

[0092] From the combination of Example 6 and Comparative Example 3 and Table 1, it can be seen that in Comparative Example 3, only sand II is stirred uniformly with polyvinyl alcohol solution and dried. Although polyvinyl alcohol has excellent bonding properties, it contains a large number of hydroxyl groups and has good hydrophilicity, which seriously affects the subsequent impermeability of concrete. This is because the epoxy groups in the added epoxy-based silicate can undergo condensation reaction with the hydroxyl groups of polyvinyl alcohol to form products containing siloxane bonds. Sand II plays an excellent modification role, giving machine-made sand II good water resistance and improving its impermeability. The sodium hydroxide solution can also give machine-made sand II a certain alkalinity, which is beneficial to the activation of cement, promotes cement hydration, changes the surface tension of concrete, makes it more easily flow and vibrate, and improves the plasticity and workability of concrete.

[0093] From the combination of Example 6 and Comparative Example 4 and Table 1, it can be seen that in Comparative Example 4, only sand III and calcium acetate solution are stirred uniformly and dried, and the comprehensive performance of the obtained concrete is also significantly decreased. This is because the poly sodium sulfonate resin can promote the dispersion of cement particles, making them more uniformly distributed in the concrete, thereby enhancing the cohesion and strength of the cement colloid. It can also react with calcium ions to form a stable composite colloidal structure, so that machine-made sand III fills the micropores and cracks in the concrete as an aggregate, reduces water penetration, improves the impermeability of the concrete, and makes the plastic concrete have good elastic modulus.

[0094] From the combination of Example 6 and Comparative Example 5 and Table 1, it can be seen that in Comparative Example 5, the acrylic acid-methyl acrylic acid copolymer is missing, and the mechanical properties of the concrete are all poor. This is because the acrylic acid-methyl acrylic acid copolymer can also form a complex with acetate ions in the system, promote the dispersion of cement particles, improve the utilization rate of cement in concrete, thereby increasing the early and long-term strength of concrete.

[0095] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for producing a plastic concrete using a manufactured sand gradation, characterized by, The method comprises the following steps: Screening the construction waste to obtain sand I, sand II and sand III with particle size >0.5 mm, particle size 0.5-0.2 mm and particle size ≤0.2 mm; Mixing and stirring sand I, coupling agent and emulsion uniformly and drying to obtain machine-made sand I; Mixing and stirring sand II and polyvinyl alcohol solution uniformly, adjusting the pH value to alkaline, adding epoxy silicate and heating to obtain machine-made sand II; Mixing and stirring sand III, calcium acetate solution and polysulfonate resin uniformly, then kneading, and then baking and activating to obtain machine-made sand III; Mixing and stirring cement, water, machine-made sand I, machine-made sand II, machine-made sand III, gravel, acrylic-methacrylic acid copolymer, admixture and additive agent uniformly. The mass ratio of sand I, coupling agent and emulsion is 10:(0.05-0.1):(2-4.5). The mass ratio of sand II, polyvinyl alcohol solution and epoxy silicate is 11:(6-9):(3-7). The mass ratio of sand III, calcium acetate solution and polysulfonate resin is 7:(5-10):(1-2). The cement is 30-45 parts by weight, the water is 10-20 parts by weight, the machine-made sand I is 10-20 parts by weight, the machine-made sand II is 25-35 parts by weight, the machine-made sand III is 20-30 parts by weight, the gravel is 100-125 parts by weight, the admixture is 9-19 parts by weight, the additive agent is 0.3-0.8 parts by weight, and the acrylic-methacrylic acid copolymer is 1-2.5 parts by weight.

2. The method for preparing a plastic concrete using a mechanism sand gradation according to claim 1, characterized in that: The emulsion comprises one of acrylic emulsion, polyurethane emulsion and styrene emulsion.

3. The method of claim 1, wherein the method is characterized by: The polysulfonate resin is sodium polysulfonate resin.

4. The method of preparing a plastic concrete with a mechanism sand gradation according to claim 1, characterized in that: The admixture comprises at least two of fly ash, mineral powder, silica ash and bentonite.

5. The method of claim 1, wherein the method is characterized by: The gravel is granite gravel or limestone gravel with particle size 5-25 mm.

6. The method of preparing a plastic concrete with a mechanism sand gradation according to claim 1, characterized in that: The additive agent comprises water reducing agent and dispersant.

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