High-impermeability regenerated micro-powder concrete and preparation method thereof

Abstract

The invention relates to the technical field of concrete, and discloses high-impermeability regenerated micro-powder concrete and a preparation method thereof. The preparation method comprises the following steps: adding 3-(methacryloyloxy) propyltrimethoxysilane into an ethanol water solution, heating to 40-60 DEG C, stirring for 1-2 hours, adding nano glass beads, continuously carrying out heat preservation and stirring for 2-4 hours, filtering, washing and drying to obtain double-bond glass beads; the preparation method comprises the following steps: taking isopentenyl polyoxyethylene ether, adding the isopentenyl polyoxyethylene ether into water, uniformly stirring, adding an initiator, and stirring and dissolving to obtain a mixed solution A; adding acrylic acid, sodium methallyl sulfonate and double-bond glass beads into water, uniformly stirring, heating to 60-70 DEG C, dropwise adding the mixed solution A for 2-3 hours, heating to 75-80 DEG C, keeping the temperature for 3-4 hours, adjusting the pH value to be neutral, filtering, and drying to obtain modified microspheres; and mixing the coarse aggregate, the fine aggregate, the regenerated micro powder, fly ash, cement, the modified microbeads, an additive and water to obtain the high-impermeability regenerated micro powder concrete.

Description

Technical Field

[0001] This invention relates to the field of concrete technology and discloses a high-permeability recycled micro-powder concrete and its preparation method. Background Technology

[0002] With the rapid development of the construction industry, the demand for sand and gravel resources is increasing, leading to higher construction costs. Recycled micro-powder, obtained from construction waste primarily composed of waste concrete, can replace some raw materials in concrete production after centralized dust collection, thus saving significant resources.

[0003] On the one hand, recycled micro-powder fills the tiny pores of cement particles and their hydration products, promoting the strength and impermeability of concrete. However, due to its numerous micropores, it absorbs free water from the slurry and adsorbs some water-reducing agents, leading to reduced fluidity and negatively impacting various properties. Therefore, researching a high-strength, high-impermeability recycled micro-powder concrete and its preparation method is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a high-permeability recycled micro-powder concrete and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing high impermeability recycled micro powder concrete, comprising the following steps: mixing coarse aggregate, fine aggregate, recycled micro powder, fly ash, cement, modified microspheres, admixtures and water to obtain high impermeability recycled micro powder concrete;

[0006] The fly ash is Xingda Grade II fly ash, with a 45μm sieve residue of no more than 25%; the recycled micro powder is obtained from construction waste, mainly waste concrete, processed through a recycling production line and after centralized dust collection, and comes from Beijing Dushi Luyuan Environmental Protection Technology Co., Ltd.; the cement is Zhonglian P·O42.5 cement with a specific surface area of ​​400 m². 2 / kg; fine aggregate is river sand with a particle size of less than 5mm and a fineness modulus of 2.6~3.0; coarse aggregate is crushed stone with a particle size of 10~15mm;

[0007] The preparation of the modified microbeads includes the following steps: S1-1: Take 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 55wt% ethanol aqueous solution, heat to 40~60℃ and stir for 1~2h, add nano glass beads, continue to keep warm and stir for 2~4h, filter, wash and dry to obtain double bonded glass beads.

[0008] S1-2: Take isopentenyl polyoxyethylene ether, add it to water and stir evenly, add initiator APS and stir to dissolve, to obtain mixed solution A; take acrylic acid, sodium methacrylate sulfonate and double-bonded glass beads, add them to water and stir evenly, heat to 60~70℃, add mixed solution A dropwise, and complete the addition in 2~3 hours, heat to 75~80℃ and keep warm for 3~4 hours, adjust the pH to neutral, filter and dry to obtain modified microbeads.

[0009] In a more optimized manner, the high-permeability recycled micro-powder concrete comprises the following raw materials, by weight: 60-80 parts coarse aggregate, 40-60 parts fine aggregate, 30-40 parts recycled micro-powder, 15-20 parts fly ash, 10-20 parts cement, 15-20 parts modified microspheres, 2-3 parts admixture, and 10-15 parts water.

[0010] In a more optimized manner, the double-bonded glass beads comprise the following raw materials, by mass parts: 1-2 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, and 10-15 parts of nano glass beads;

[0011] The modified microspheres comprise the following raw materials, by mass: 10-15 parts isopentenyl polyoxyethylene ether, 0.4-0.5 parts initiator, 1-2 parts acrylic acid, 4-5 parts sodium methacrylate sulfonate, and 80-100 parts double-bonded glass beads.

[0012] More preferably, the admixture includes a two-arm water-reducing agent and sodium ethylenediaminetetraacetate;

[0013] The preparation of the two-arm water-reducing agent refers to the prior art and includes the following steps: S2-1: Take methoxy polyethylene glycol chloride, add dimethyl sulfoxide (DMSO) and stir to dissolve, add potassium carbonate, potassium iodide, and ethanolamine, stir at 80-85°C for 20-30 hours under nitrogen protection, remove the solvent, add dimethyl sulfoxide and stir evenly, add potassium carbonate, add a mixture of acryloyl chloride and dimethyl sulfoxide in an ice bath under dark conditions and nitrogen protection, react for 20-30 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0014] S2-2: Take two-arm polyoxyethylene ether, add it to water and stir evenly, add initiator, stir to dissolve, and obtain mixed solution B; take acrylic acid and sodium methacrylate, add them to water, stir evenly, heat to 60~70℃, add mixed solution B dropwise, and finish adding in 2~3 hours, heat to 75~80℃ and keep warm for 3~4 hours, adjust pH to 7, remove solvent, and obtain two-arm water-reducing agent;

[0015] This step uses ethanolamine as the core, which undergoes affinity substitution with methoxy polyethylene glycol chloride. To ensure that both hydrogen atoms on the amine group are substituted, an excess of methoxy polyethylene glycol chloride is used. After the amine group of ethanolamine is completely substituted, a carbon-carbon double bond is introduced through acryloyl chloride to obtain a two-armed polyoxyethylene ether.

[0016] Ideally, the mass ratio of the two-arm water-reducing agent to sodium ethylenediaminetetraacetate is (1~3):1.

[0017] More preferably, the two-arm polyoxyethylene ether comprises the following raw materials, in parts by mass: 120-150 parts methoxy polyethylene glycol chloride, 2-3 parts ethanolamine, and 8-15 parts acryloyl chloride;

[0018] The two-arm water-reducing agent comprises the following raw materials, by mass parts: 10-15 parts of two-arm polyoxyethylene ether, 0.4-0.5 parts of initiator, 1-2 parts of acrylic acid, and 4-5 parts of sodium methacrylate sulfonate.

[0019] More preferably, the isopentenyl polyoxyethylene ether is TPEG2400; and the methoxy polyethylene glycol chloride has a molecular weight of 1k.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are: the addition of recycled micro powder promotes the performance of concrete, but due to the large number of micropores inside, it will absorb water and water-reducing agent in the slurry, and the recycled micro powder has a layered structure, which makes it difficult to provide rolling lubrication, resulting in reduced fluidity and affecting the overall performance.

[0021] Therefore, this invention introduces modified microspheres, using nano-glass beads as raw materials, to enhance rolling lubrication. Their small particle size allows them to form a continuous gradation with other particles, resulting in denser particle packing. After modification, the nano-glass beads are grafted with a water-reducing agent. Part of this agent is adsorbed by the recycled micropowder, improving the bonding force between the recycled micropowder and the modified microspheres, while the other part enhances overall dispersibility. Simultaneously, this invention also introduces admixtures. The two-arm water-reducing agent, compared to the water-reducing agent grafted onto the modified microsphere surface, has a similar structure but greater steric hindrance, making it less susceptible to adsorption by the recycled micropowder, thus providing excellent flowability. Sodium ethylenediaminetetraacetate, as a small molecule additive, has complexing properties for metal ions, rapidly dispersing hydration products and thereby enhancing the strength of concrete.

[0022] In summary, this solution improves the problem of decreased fluidity caused by the introduction of recycled micropowder by introducing modified microspheres and admixtures, and finally produces high-strength and highly impermeable concrete materials. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that there are no special restrictions on the suppliers of any of the raw materials involved in this invention. Exemplary examples include: fly ash is Xingda Grade II fly ash, with a 45μm sieve residue of no more than 25%; the recycled micro powder is obtained from construction waste, primarily waste concrete, processed through a recycling production line and after centralized dust collection, and originates from Beijing Dushi Luyuan Environmental Protection Technology Co., Ltd.; the cement is Zhonglian P·O42.5 cement with a specific surface area of ​​400m². 2 / kg; fine aggregate is river sand with a particle size of less than 5mm and a fineness modulus of 2.6~3.0; coarse aggregate is crushed stone with a particle size of 10~15mm;

[0025] Ethanol (CAS: 64-17-5); Dimethyl sulfoxide (DMSO); 3-(isobutenoyloxy)propyltrimethoxysilane (CAS: 2530-85-0); Nano glass beads (SH-516, Guangzhou Shuanghong Building Materials Co., Ltd.); Isoprene polyoxyethylene ether (TPEG2400, Wuhan Kanos); Initiator APS (Ammonium persulfate, CAS: 7727-54-0); Sodium ethylenediaminetetraacetate (EDTA-DICA disodium salt dihydrate, S30026, Shanghai Yuanye); Methoxy polyethylene glycol chloride (Tansh, molecular weight 1k); Potassium carbonate (anhydrous potassium carbonate, Shanghai Yuanye); Potassium iodide (S30393, Shanghai Yuanye); Ethanolamine (CAS: 141-43-5); Acryloyl chloride (CAS: 814-68-6);

[0026] Unless otherwise specified, all figures below are parts by weight or mass ratios.

[0027] Example 1: Step 1: S1-1: Take 1.5 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 50 parts of 55wt% ethanol aqueous solution, heat to 50℃ and stir for 1h, add 10 parts of nano glass beads, continue to keep warm and stir for 4h, filter, wash and dry to obtain double bonded glass beads.

[0028] S1-2: Take 12 parts of isopentenyl polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; take 1.5 parts of acrylic acid, 4.5 parts of sodium methacrylate sulfonate, 100 parts of double-bonded glass beads, add 200 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, filter and dry to obtain modified microbeads;

[0029] Step 2: S2-1: Take 120 parts of methoxy polyethylene glycol chloride, add 100 parts of DMSO, stir to dissolve, add 28 parts of potassium carbonate, 0.8 parts of potassium iodide, and 2.5 parts of ethanolamine, stir at 80°C for 24 hours under nitrogen protection, remove the solvent, add 80 parts of DMSO and stir evenly, then add 25 parts of potassium carbonate, use ice to make an ice bath, under dark conditions and nitrogen protection, add a mixture of 12 parts of acryloyl chloride and 20 parts of DMSO, add over 30 minutes, react for 24 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0030] S2-2: Take 13 parts of two-arm polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution B; take 1.5 parts of acrylic acid and 4.5 parts of sodium methacrylate sulfonate, add 30 parts of water, stir evenly, heat to 60℃, add mixed solution B dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain two-arm water-reducing agent;

[0031] S2-3: Mix the two-arm water-reducing agent and sodium ethylenediaminetetraacetate in a mass ratio of 2:1 to obtain the admixture;

[0032] Step 3: Mix 70 parts coarse aggregate, 50 parts fine aggregate, 35 parts recycled micro powder, 16 parts fly ash, 18 parts cement, 18 parts modified microspheres, 2 parts admixture, and 10 parts water to obtain high impermeability recycled micro powder concrete.

[0033] Example 2: Step 1: S1-1: Take 1.5 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 50 parts of 55wt% ethanol aqueous solution, heat to 50℃ and stir for 1 hour, add 10 parts of nano glass beads, continue to keep warm and stir for 4 hours, filter, wash and dry to obtain double bonded glass beads.

[0034] S1-2: Take 10 parts of isopentenyl polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; take 1 part of acrylic acid, 4 parts of sodium methacrylate sulfonate, 80 parts of double-bonded glass beads, add 200 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, filter and dry to obtain modified microbeads;

[0035] Step 2: S2-1: Take 120 parts of methoxy polyethylene glycol chloride, add 100 parts of DMSO, stir to dissolve, add 30 parts of potassium carbonate, 0.8 parts of potassium iodide, and 2.5 parts of ethanolamine, stir at 80°C for 24 hours under nitrogen protection, remove the solvent, add 80 parts of DMSO and stir evenly, then add 30 parts of potassium carbonate, use ice to make an ice bath, under dark conditions and nitrogen protection, add a mixture of 15 parts of acryloyl chloride and 20 parts of DMSO, add over 30 minutes, react for 24 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0036] S2-2: Take 10 parts of two-arm polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution B; take 1 part of acrylic acid and 4 parts of sodium methacrylate sulfonate, add 30 parts of water, stir evenly, heat to 60℃, add mixed solution B dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain two-arm water-reducing agent;

[0037] S2-3: Mix the two-arm water-reducing agent and sodium ethylenediaminetetraacetate in a mass ratio of 2:1 to obtain the admixture;

[0038] Step 3: Mix 60 parts coarse aggregate, 40 parts fine aggregate, 30 parts recycled micro powder, 15 parts fly ash, 12 parts cement, 20 parts modified microspheres, 2 parts admixture, and 10 parts water to obtain high impermeability recycled micro powder concrete.

[0039] Example 3: Step 1: S1-1: Take 1.5 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 50 parts of 55wt% ethanol aqueous solution, heat to 50℃ and stir for 1h, add 10 parts of nano glass beads, continue to keep warm and stir for 4h, filter, wash and dry to obtain double bonded glass beads.

[0040] S1-2: Take 15 parts of isopentenyl polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; take 2 parts of acrylic acid, 5 parts of sodium methacrylate sulfonate, 100 parts of double-bonded glass beads, add 200 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, filter and dry to obtain modified microbeads;

[0041] Step 2: S2-1: Take 120 parts of methoxy polyethylene glycol chloride, add 100 parts of DMSO, stir to dissolve, add 25 parts of potassium carbonate, 0.8 parts of potassium iodide, and 2.5 parts of ethanolamine, stir at 80°C for 24 hours under nitrogen protection, remove the solvent, add 80 parts of DMSO and stir evenly, then add 30 parts of potassium carbonate, use ice to make an ice bath, under dark conditions and nitrogen protection, add a mixture of 15 parts of acryloyl chloride and 20 parts of DMSO, add over 30 minutes, react for 24 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0042] S2-2: Take 15 parts of two-arm polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution B; take 2 parts of acrylic acid and 5 parts of sodium methacrylate sulfonate, add 30 parts of water, stir evenly, heat to 60℃, add mixed solution B dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain two-arm water-reducing agent;

[0043] S2-3: Mix the two-arm water-reducing agent and sodium ethylenediaminetetraacetate in a mass ratio of 2:1 to obtain the admixture;

[0044] Step 3: Mix 80 parts coarse aggregate, 60 parts fine aggregate, 40 parts recycled micro powder, 20 parts fly ash, 20 parts cement, 20 parts modified microspheres, 3 parts admixture, and 15 parts water to obtain high impermeability recycled micro powder concrete.

[0045] Comparative Example 1 (using nano glass beads instead of modified microspheres, the rest of the methods and steps are the same as in Example 1): Step 1: Use nano glass beads instead of modified microspheres;

[0046] Step 2: S2-1: Take 120 parts of methoxy polyethylene glycol chloride, add 100 parts of DMSO, stir to dissolve, add 28 parts of potassium carbonate, 0.8 parts of potassium iodide, and 2.5 parts of ethanolamine, stir at 80°C for 24 hours under nitrogen protection, remove the solvent, add 80 parts of DMSO and stir evenly, then add 25 parts of potassium carbonate, use ice to make an ice bath, under dark conditions and nitrogen protection, add a mixture of 12 parts of acryloyl chloride and 20 parts of DMSO, add over 30 minutes, react for 24 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0047] S2-2: Take 13 parts of two-arm polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution B; take 1.5 parts of acrylic acid and 4.5 parts of sodium methacrylate sulfonate, add 30 parts of water, stir evenly, heat to 60℃, add mixed solution B dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain two-arm water-reducing agent;

[0048] S2-3: Mix the two-arm water-reducing agent and sodium ethylenediaminetetraacetate in a mass ratio of 2:1 to obtain the admixture;

[0049] Step 3: Mix 70 parts coarse aggregate, 50 parts fine aggregate, 35 parts recycled micro powder, 16 parts fly ash, 18 parts cement, 18 parts nano glass beads, 2 parts admixture, and 10 parts water to obtain high impermeability recycled micro powder concrete.

[0050] Comparative Example 2 (using glass fibers (diameter 0.1~0.2 mm, length 10~15 mm) instead of nano glass beads, the remaining methods and steps are the same as in Example 1): Step 1: Use glass fibers (diameter 0.1~0.2 mm, length 10~15 mm) instead of nano glass beads to prepare modified fibers. To replace the modified microbeads: Take 1.5 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 50 parts of 55wt% ethanol aqueous solution, heat to 50℃ and stir for 1 h, add 10 parts of glass fibers, continue to keep warm and stir for 4 h, filter, wash and dry to obtain double-bonded glass fibers;

[0051] Take 12 parts of isopentenyl polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; take 1.5 parts of acrylic acid, 4.5 parts of sodium methacrylate sulfonate, 100 parts of double-bonded glass fiber, add 200 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, filter and dry to obtain modified fiber;

[0052] Step 2: S2-1: Take 120 parts of methoxy polyethylene glycol chloride, add 100 parts of DMSO, stir to dissolve, add 28 parts of potassium carbonate, 0.8 parts of potassium iodide, and 2.5 parts of ethanolamine, stir at 80°C for 24 hours under nitrogen protection, remove the solvent, add 80 parts of DMSO and stir evenly, then add 25 parts of potassium carbonate, use ice to make an ice bath, under dark conditions and nitrogen protection, add a mixture of 12 parts of acryloyl chloride and 20 parts of DMSO, add over 30 minutes, react for 24 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0053] S2-2: Take 13 parts of two-arm polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution B; take 1.5 parts of acrylic acid and 4.5 parts of sodium methacrylate sulfonate, add 30 parts of water, stir evenly, heat to 60℃, add mixed solution B dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain two-arm water-reducing agent;

[0054] S2-3: Mix the two-arm water-reducing agent and sodium ethylenediaminetetraacetate in a mass ratio of 2:1 to obtain the admixture;

[0055] Step 3: Mix 70 parts coarse aggregate, 50 parts fine aggregate, 35 parts recycled micro powder, 16 parts fly ash, 18 parts cement, 18 parts modified fiber, 2 parts admixture, and 10 parts water to obtain high impermeability recycled micro powder concrete.

[0056] Comparative Example 3 (using a water-reducing agent instead of a two-arm water-reducing agent, with the remaining methods and steps being the same as in Example 1): Step 1: S1-1: Take 1.5 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 50 parts of 55wt% ethanol aqueous solution, heat to 50℃ and stir for 1 hour, add 10 parts of nano glass beads, continue to keep warm and stir for 4 hours, filter, wash and dry to obtain double-bonded glass beads;

[0057] S1-2: Take 12 parts of isopentenyl polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; take 1.5 parts of acrylic acid, 4.5 parts of sodium methacrylate sulfonate, 100 parts of double-bonded glass beads, add 200 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, filter and dry to obtain modified microbeads;

[0058] Step 2: Prepare a water-reducing agent to replace the two-arm water-reducing agent in the admixture: Take 12 parts of isopentenyl polyoxyethylene ether, add it to 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; Take 1.5 parts of acrylic acid and 4.5 parts of sodium methacrylate sulfonate, add them to 30 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain the water-reducing agent;

[0059] The water-reducing agent and sodium ethylenediaminetetraacetate were mixed in a mass ratio of 2:1 to obtain the admixture;

[0060] Step 3: Mix 70 parts coarse aggregate, 50 parts fine aggregate, 35 parts recycled micro powder, 16 parts fly ash, 18 parts cement, 18 parts modified microspheres, 2 parts admixture, and 10 parts water to obtain high impermeability recycled micro powder concrete.

[0061] Comparative Example 4 (using a two-arm water-reducing agent as an admixture, with the remaining methods and steps being the same as in Example 1): Step 1: S1-1: Take 1.5 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, add it to 50 parts of 55wt% ethanol aqueous solution, heat to 50℃ and stir for 1 hour, add 10 parts of nano glass beads, continue to keep warm and stir for 4 hours, filter, wash and dry to obtain double-bonded glass beads;

[0062] S1-2: Take 12 parts of isopentenyl polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution A; take 1.5 parts of acrylic acid, 4.5 parts of sodium methacrylate sulfonate, 100 parts of double-bonded glass beads, add 200 parts of water, stir evenly, heat to 60℃, add mixed solution A dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, filter and dry to obtain modified microbeads;

[0063] Step 2: Directly use the two-arm water-reducing agent as an admixture: Take 120 parts of methoxy polyethylene glycol chloride, add 100 parts of DMSO, stir to dissolve, add 28 parts of potassium carbonate, 0.8 parts of potassium iodide, and 2.5 parts of ethanolamine, stir at 80°C for 24 hours under nitrogen protection, remove the solvent, add 80 parts of DMSO and stir evenly, then add 25 parts of potassium carbonate, use ice to make an ice bath, under dark conditions and nitrogen protection, add a mixture of 12 parts of acryloyl chloride and 20 parts of DMSO, add for 30 minutes, react for 24 hours, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether;

[0064] Take 13 parts of two-arm polyoxyethylene ether, add 60 parts of water and stir evenly, add 0.4 parts of initiator APS, stir to dissolve, and obtain mixed solution B; take 1.5 parts of acrylic acid and 4.5 parts of sodium methacrylate sulfonate, add 30 parts of water, stir evenly, heat to 60℃, add mixed solution B dropwise, and complete the addition in 2 hours, heat to 75℃ and keep warm for 4 hours, adjust the pH to 7, remove the solvent, and obtain two-arm water-reducing agent, which is used as an admixture;

[0065] Step 3: Mix 70 parts coarse aggregate, 50 parts fine aggregate, 35 parts recycled micro powder, 16 parts fly ash, 18 parts cement, 18 parts modified microspheres, 2 parts admixture, and 10 parts water to obtain high impermeability recycled micro powder concrete.

[0066] Performance testing: High impermeability recycled micro-powder concrete prepared in Examples 1-3 and Comparative Examples 1-4 was used; (1) 28-day compressive strength was tested according to GB / T50081-2002; (2) impermeability was tested according to GB / T50082-2009; (3) spreadability was tested according to GB / T50080-2016 to evaluate flowability; see Table 1 for details.

[0067] Table 1:

[0068]

[0069] Conclusions: In Comparative Example 1, the performance of the unmodified microspheres replaced with nano-glass beads was significantly reduced. In Comparative Example 2, the performance of the nano-glass beads was reduced due to changes in morphology and fluidity. In Comparative Example 3, the performance of the two-arm water-reducing agent was reduced due to the decrease in steric hindrance. In Comparative Example 4, the performance of the two-arm water-reducing agent was significantly worse than that of the examples without the addition of the small molecule admixture sodium EDTA. In summary, the high impermeability recycled micro-powder concrete prepared by this invention has excellent strength and impermeability.

[0070] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing highly impermeable recycled micro-powder concrete, characterized in that: Includes the following steps: Step 1: S1-1: Take 3-(isobutenoyloxy)propyltrimethoxysilane, add it to an aqueous ethanol solution, heat to 40~60℃ and stir for 1~2h, add nano glass beads, continue to keep warm and stir for 2~4h, filter, wash and dry to obtain double-bonded glass beads. S1-2: Take isopentenyl polyoxyethylene ether, add it to water and stir evenly, add initiator and stir to dissolve, to obtain mixed solution A; take acrylic acid, sodium methacrylate sulfonate and double-bonded glass beads, add them to water and stir evenly, heat to 60~70℃, add mixed solution A dropwise, and finish adding in 2~3 hours, heat to 75~80℃ and keep warm for 3~4 hours, adjust the pH to neutral, filter and dry to obtain modified microbeads; Step 2: Combine the water-reducing agent and sodium ethylenediaminetetraacetate to obtain the admixture; Step 3: Mix coarse aggregate, fine aggregate, recycled micro powder, fly ash, cement, modified microspheres, admixtures, and water to obtain high impermeability recycled micro powder concrete.

2. The method for preparing high-permeability recycled micro-powder concrete according to claim 1, characterized in that: The high impermeability recycled micro-powder concrete comprises the following raw materials, by weight: 60-80 parts coarse aggregate, 40-60 parts fine aggregate, 30-40 parts recycled micro-powder, 15-20 parts fly ash, 10-20 parts cement, 15-20 parts modified microspheres, 2-3 parts admixture, and 10-15 parts water.

3. The method for preparing high-permeability recycled micro-powder concrete according to claim 1, characterized in that: The double-bonded glass beads comprise the following raw materials, by mass: 1-2 parts of 3-(isobutenoyloxy)propyltrimethoxysilane, and 10-15 parts of nano glass beads; The modified microspheres comprise the following raw materials, by mass: 10-15 parts isopentenyl polyoxyethylene ether, 0.4-0.5 parts initiator, 1-2 parts acrylic acid, 4-5 parts sodium methacrylate sulfonate, and 80-100 parts double-bonded glass beads.

4. The method for preparing high-permeability recycled micro-powder concrete according to claim 1, characterized in that: The water-reducing agent is a two-arm water-reducing agent; The preparation of the two-arm water-reducing agent includes the following steps: S2-1: Take methoxy polyethylene glycol chloride, add dimethyl sulfoxide and stir to dissolve, add potassium carbonate, potassium iodide and ethanolamine, stir at 80~85℃ for 20~30h under nitrogen protection, remove the solvent, add dimethyl sulfoxide and stir evenly, add potassium carbonate, in an ice bath and under dark conditions and nitrogen protection, add a mixture of acryloyl chloride and dimethyl sulfoxide, react for 20~30h, filter and rotary evaporate to remove impurities, and obtain two-arm polyoxyethylene ether; S2-2: Take two-arm polyoxyethylene ether, add it to water and stir evenly, add initiator, stir to dissolve, and obtain mixed solution B; take acrylic acid and sodium methacrylate, add them to water, stir evenly, heat to 60~70℃, add mixed solution B dropwise, and finish adding in 2~3 hours, heat to 75~80℃ and keep warm for 3~4 hours, adjust pH to 7, remove solvent, and obtain two-arm water-reducing agent.

5. The method for preparing high-permeability recycled micro-powder concrete according to claim 4, characterized in that: The mass ratio of the two-arm water-reducing agent to sodium ethylenediaminetetraacetate is (1~3):

1.

6. The method for preparing highly impermeable recycled micro-powder concrete according to claim 4, characterized in that: The two-arm polyoxyethylene ether comprises the following raw materials, in parts by mass: 120-150 parts of methoxy polyethylene glycol chloride, 2-3 parts of ethanolamine, and 8-15 parts of acryloyl chloride; The two-arm water-reducing agent comprises the following raw materials, by mass parts: 10-15 parts of two-arm polyoxyethylene ether, 0.4-0.5 parts of initiator, 1-2 parts of acrylic acid, and 4-5 parts of sodium methacrylate sulfonate.

7. The method for preparing high-permeability recycled micro-powder concrete according to claim 1, characterized in that: The isopentenyl polyoxyethylene ether is TPEG2400.

8. The method for preparing high-permeability recycled micro-powder concrete according to claim 4, characterized in that: The methoxy polyethylene glycol chloride has a molecular weight of 1k.

9. Concrete prepared by the method for preparing high impermeability recycled micro-powder concrete according to any one of claims 1 to 8.

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