Polyurethane concrete based on solid waste materials and method for its preparation

Abstract

This invention relates to the field of polyurethane concrete processing technology, and discloses a polyurethane concrete based on solid waste materials and its preparation method, comprising the following raw materials in parts by weight: 20-30 parts of single-component polyurethane adhesive, 2-5 parts of asphalt, 38-42 parts of road waste concrete, 5-10 parts of reinforcing filler, 15-20 parts of manufactured sand, 6-8 parts of aggregate, 6-9 parts of mineral powder, and 2-3 parts of curing agent. The polyurethane concrete prepared using this technical solution exhibits good mechanical properties and impermeability.

Description

Technical Field

[0001] This invention relates to the field of polyurethane concrete processing technology, specifically to a polyurethane concrete based on solid waste materials and its preparation method. Background Technology

[0002] Currently, hot-mix asphalt concrete is the most commonly used pavement material for large-span, high-volume bridges, tunnels, and other special road surfaces. However, it is easily affected by external environmental factors and vehicle loads, resulting in various pavement defects such as ruts, cracks, and potholes, which greatly reduces the service life of the pavement. Polyurethane concrete is a new type of road pavement material that uses polyurethane to replace part of the cement as a binder. It has the advantages of cold mixing and cold laying, being environmentally friendly, having superior road performance, and good durability. It can fully meet the performance requirements of existing road pavement materials and has been applied in many projects.

[0003] Polyurethane concrete is prepared by mixing road waste concrete with polyurethane adhesive, cement, new aggregate, fly ash, and additives, thus realizing the recycling of road waste concrete. Among them, fly ash, as a reinforcing filler, can fill the micro-cracks or pore channels of concrete and improve the mechanical properties of concrete. However, fly ash has a porous structure and is easy to absorb moisture, resulting in poor impermeability of polyurethane concrete and affecting the mechanical strength of concrete. Summary of the Invention

[0004] This invention provides a polyurethane concrete based on solid waste materials and its preparation method, which solves the problem that fly ash easily absorbs moisture in polyurethane concrete slurry, resulting in poor impermeability of the concrete.

[0005] The technical solution of the present invention:

[0006] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 20-30 parts of single-component polyurethane adhesive, 38-42 parts of road waste concrete, 5-10 parts of reinforcing filler, 15-20 parts of manufactured sand, 6-8 parts of stone, 6-9 parts of mineral powder, 15-20 parts of cement, 0.5-1 part of water-reducing agent, and 2-3 parts of curing agent.

[0007] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0008] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 300-400 r / min for 8-10 min to obtain the mixture;

[0009] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 30-40℃ for 8-10 minutes to obtain polyurethane concrete;

[0010] Furthermore, the reinforcing filler is obtained by synthesizing calcium carbonate from chitosan-modified fly ash, then mixing and reacting it with stearic acid, and finally coating the surface with an amphiphilic modifier.

[0011] Furthermore, the amphiphilic modifier is obtained by modifying carboxymethyl cellulose with a silane coupling agent and then copolymerizing it with divinylbenzene.

[0012] Furthermore, the pretreated fly ash is obtained by mixing fly ash, sodium hydroxide, epichlorohydrin and chitosan solution, reacting them, then mixing them with calcium chloride, and reacting them with carbon dioxide.

[0013] Furthermore, the manufactured sand has a particle size of 4-4.5 mm and an apparent density of 2500-2600 kg / m³. 3 .

[0014] Furthermore, the stone material is selected from any one of basalt gravel, limestone, or natural sand.

[0015] Furthermore, the mineral powder is S95 grade slag powder with a density of 2.5-3.9 g / cm³. 3 Specific surface area is 445-460 m² 2 / kg.

[0016] Furthermore, the curing agent is a mixture of ethylene glycol, petroleum ether, water and cumene hydrogen peroxide at room temperature, with a mass ratio of ethylene glycol, petroleum ether, water and cumene hydrogen peroxide of 3-4:2-3:2-4:1-2.

[0017] Furthermore, the water-reducing agent is any one of PCE-102 polycarboxylate water-reducing agent, PCE-101 polycarboxylate water-reducing agent, and PCE-103 polycarboxylate water-reducing agent.

[0018] Furthermore, the cement is grade 42.5 low-alkalinity sulfoaluminate cement.

[0019] Furthermore, the reinforcing filler is specifically prepared by the following steps:

[0020] A1. Mix fly ash, acetone and sodium hydroxide, stir at 50-60℃ for 20-30 min, add to epichlorohydrin, stir, add chitosan solution, continue stirring, filter, wash and dry to obtain chitosan modified fly ash;

[0021] A2. Add calcium chloride to deionized water and stir at 70-80℃ until completely dissolved. Add chitosan-modified fly ash and stir at 80-90℃ for 1-3 hours. Cool to room temperature, introduce carbon dioxide, and stir for 1-2 hours. After filtration, washing, and drying, pretreated fly ash is obtained.

[0022] A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 50-60℃ for 20-30 minutes, filter, wash and dry to obtain modified fly ash;

[0023] A4. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 5-6 hours, and dry to obtain the reinforced filler.

[0024] Furthermore, in the A1 reaction process described above, the fly ash is activated by sodium hydroxide, which can remove impurities from the surface of the fly ash and introduce active groups on the surface of the fly ash. The introduced active group hydroxyl can undergo a ring-opening reaction with epichlorohydrin, and the chlorine atom of epichlorohydrin undergoes a substitution reaction with the amino group of chitosan, so that chitosan is grafted into the pores of the fly ash as a synthesis site for calcium carbonate.

[0025] Furthermore, in the A2 reaction process described above, the amino and hydroxyl groups contained in the chitosan in the chitosan-modified fly ash can combine with calcium ions in calcium chloride, allowing calcium ions to be adsorbed into the pores of the chitosan-modified fly ash. The introduced carbon dioxide can provide carbonate ions, which can form calcium carbonate with calcium ions, thereby achieving the synthesis of calcium carbonate in the pores of the chitosan-modified fly ash and obtaining pretreated fly ash.

[0026] Furthermore, during the A3 reaction process described above, the calcium carbonate contained in the pores of the pretreated fly ash hydrolyzes. The hydrolysis occurs on the surface of the calcium carbonate, which in turn generates calcium ions on the surface of the calcium carbonate. These ions can react with stearic acid to form calcium stearate, thereby introducing calcium stearate into the pores of the pretreated fly ash and obtaining modified fly ash.

[0027] Furthermore, during the A4 reaction process described above, the hydrophobic chains contained in the amphiphilic modifier can interact with the stearic acid in the modified fly ash, and the carboxymethyl cellulose contained in the amphiphilic modifier has adhesive properties, which allows the amphiphilic modifier to coat the surface of the modified fly ash, thus obtaining a reinforcing filler.

[0028] Further, in step A1, the mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin and chitosan solution is 10:(10-20):(5-10):(10-15):(2-5).

[0029] Furthermore, in step A2, the mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash is (1-2):(50-55):10.

[0030] Further, in step A3, the mass ratio of pretreated fly ash, deionized water and stearic acid is 10:(50-60):(2-3).

[0031] Further, in step A4, the mass ratio of the amphiphilic modifier, ethanol, and modified fly ash is (2-5):(60-70):10.

[0032] Furthermore, the chitosan solution is prepared by mixing chitosan and acetic acid in a mass ratio of (2-3):(50-60).

[0033] Furthermore, the amphiphilic modifier is prepared by the following steps:

[0034] B1. Add carboxymethyl cellulose to ethanol and deionized water, stir well, add silane coupling agent, stir and react at 65-75℃ for 1-2 hours, cool to room temperature, filter, wash and dry to obtain modified carboxymethyl cellulose.

[0035] B2. Add modified carboxymethyl cellulose to ethanol, stir until homogeneous, add divinylbenzene and benzoyl peroxide, stir and react at 75-80℃ for 1-2 hours, dry to remove the organic solvent ethanol, and obtain the amphiphilic modifier.

[0036] Furthermore, during the B1 reaction described above, the hydroxyl groups generated by the hydrolysis of the silane coupling agent are chemically bonded to the oxygen-containing functional groups on the upper part of carboxymethyl cellulose, thereby grafting the silane coupling agent onto the carboxymethyl cellulose and obtaining modified carboxymethyl cellulose.

[0037] Furthermore, in the B2 reaction process described above, benzoyl peroxide acts as an initiator, causing divinylbenzene to undergo a polymerization reaction. The double bonds in the modified carboxymethyl cellulose are embedded into the main chain of the divinylbenzene polymer through free radical chain growth, thereby achieving the grafting of modified carboxymethyl cellulose onto the divinylbenzene polymer to obtain an amphiphilic modifier.

[0038] Further, in step B1, the mass ratio of carboxymethyl cellulose, ethanol, deionized water and silane coupling agent is (2-3):(25-35):(10-20):(0.5-1).

[0039] Further, in step B2, the mass ratio of modified carboxymethyl cellulose, ethanol, divinylbenzene and benzoyl peroxide is (3-4):(40-50):(5-6):(0.1-0.3).

[0040] Furthermore, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0041] The present invention has the following beneficial effects:

[0042] (1) In the technical solution of the present invention, fly ash is used as a reinforcing filler, which can fill the microcracks or pore channels of concrete and improve the mechanical properties of concrete; chitosan grafted into the pores of fly ash serves as a synthesis site for calcium carbonate, which is beneficial to reduce the porosity of fly ash and improve the impermeability of fly ash; calcium carbonate is generated in situ in the pores of chitosan-modified fly ash, which can block the pore structure of fly ash, effectively reduce the porosity of fly ash, improve the impermeability of fly ash, and prevent fly ash from easily absorbing water and reducing the mechanical strength of polyurethane concrete.

[0043] (2) In the technical solution of the present invention, the pretreated fly ash reacts with stearic acid to introduce calcium stearate into the pores of the pretreated fly ash. On the one hand, the calcium stearate structure is synthesized in the pores of the pretreated fly ash. The aliphatic chains contained therein can give the fly ash excellent hydrophobic properties, improve the hydrophobic properties of the fly ash, and avoid the fly ash from easily absorbing water, which would lead to a decrease in the mechanical strength of the concrete and affect the anti-rutting performance of polyurethane concrete. On the other hand, the stearic acid chains are intertwined to form a cross-linked network structure, which can prevent the migration and precipitation of calcium carbonate and enhance the stability of calcium carbonate in fly ash.

[0044] (3) In the technical solution of the present invention, silane coupling agent is used to modify carboxymethyl cellulose, and then copolymerizes it with divinylbenzene to form an amphiphilic modifier that coats the surface of the pretreated fly ash. On the one hand, the carboxymethyl cellulose contained in the amphiphilic modifier has excellent adhesion properties, which gives the fly ash excellent adhesion and improves the bonding force between the fly ash and the polyurethane concrete filler, thus avoiding poor bonding force of the fly ash in the concrete and affecting the mechanical strength of the concrete. On the other hand, the amphiphilic modifier contains a hydrophobic porous structure, which coats the surface of the modified fly ash and can be compounded with calcium stearate to further adsorb and fix the calcium carbonate component synthesized in the modified fly ash, thereby further improving the stability of calcium carbonate in the modified fly ash.

[0045] (4) In the technical solution of the present invention, the amphiphilic modifier contains a small amount of divinylbenzene polymer, the carbon chain structure of which can be intercalated into the gaps of concrete, enhance the compatibility of fly ash in polyurethane concrete slurry, improve the density and mechanical properties of concrete, avoid poor compatibility between reinforcing filler and polyurethane concrete, which would lead to the phenomenon of potholes in polyurethane concrete pavement, and improve the anti-rutting performance of polyurethane concrete.

[0046] (5) In the technical solution of the present invention, a single-component polyurethane adhesive and a small amount of asphalt are used as adhesives, road waste concrete is used as stone, and fine sand, basalt and mineral powder are used as fillers. The polyurethane concrete prepared by compounding and reinforcing fillers has good mechanical properties, porosity and impermeability. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] The raw materials used in the embodiments of this invention are shown below, and all reagents used are analytical grade.

[0049] Among them, road waste concrete is obtained by hammering and sieving road waste concrete blocks, and the particle size of road waste concrete is 10.5mm.

[0050] One-component polyurethane adhesive, part number PU299, manufactured by Shenzhen Rose Red Leaf Adhesive Products Co., Ltd.

[0051] The manufactured sand has a particle size of 4.3 mm and an apparent density of 2550 kg / m³. 3 .

[0052] The stone material is selected from basalt crushed stone, with a continuous gradation of 15mm and a mud content of 0.15%.

[0053] The mineral powder is S95 grade slag powder with a density of 2.99 g / cm³. 3 Specific surface area is 450m² 2 / kg.

[0054] The cement is grade 42.5 low-alkalinity sulfoaluminate cement.

[0055] The water-reducing agent is PCE-102 polycarboxylate water-reducing agent.

[0056] The curing agent is a mixture of ethylene glycol, petroleum ether, water and cumene hydrogen peroxide at room temperature, with a mass ratio of 3:2:2:1.

[0057] The fly ash particle size is 10μm.

[0058] Carboxymethyl cellulose, analytical grade, purchased from Tianjin Kemei Chemical Reagent Co., Ltd.

[0059] The chitosan solution is prepared by mixing chitosan and acetic acid in a mass ratio of 2.5:55.

[0060] Example 1

[0061] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 20 parts of single-component polyurethane adhesive, 38 parts of road waste concrete, 5 parts of reinforcing filler, 15 parts of manufactured sand, 6 parts of stone, 6 parts of mineral powder, 15 parts of cement, 0.5 parts of water-reducing agent, and 2 parts of curing agent.

[0062] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0063] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 300 r / min for 8 min to obtain the mixture;

[0064] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 30°C for 8 minutes to obtain polyurethane concrete.

[0065] The reinforcing filler is prepared by the following steps:

[0066] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 50°C for 20 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:10:5:10:2.

[0067] A2. Add calcium chloride to deionized water and stir at 70°C until completely dissolved. Add chitosan-modified fly ash and stir at 80°C for 1 hour. Cool to room temperature, introduce carbon dioxide, and stir for 1 hour. After filtration, wash three times with deionized water and dry in a 70°C oven for 20 minutes to obtain pretreated fly ash. The mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash is 1:50:10.

[0068] A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 50℃ for 20 min, filter, wash 3 times with deionized water, and dry in an oven at 100℃ for 5 min to obtain modified fly ash; the mass ratio of pretreated fly ash, deionized water and stearic acid is 10:50:2.

[0069] A4. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 5 hours, and dry in a 105℃ constant temperature oven for 12 hours to obtain the reinforced filler; the mass ratio of amphiphilic modifier, ethanol and modified fly ash is 2:60:10.

[0070] The amphiphilic modifier is prepared by the following steps:

[0071] B1. Carboxymethyl cellulose was added to ethanol and deionized water and stirred until homogeneous. γ-methacryloyloxypropyltrimethoxysilane was then added and stirred at 65°C for 1 hour. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain modified carboxymethyl cellulose. The mass ratio of carboxymethyl cellulose, ethanol, deionized water, and γ-methacryloyloxypropyltrimethoxysilane was 2:25:10:0.5.

[0072] B2. Modified carboxymethyl cellulose was added to ethanol and stirred until homogeneous. Divinylbenzene and benzoyl peroxide were then added and stirred at 75°C for 1 hour. The mixture was then dried at 90°C for 12 hours to remove the organic solvent ethanol, thus obtaining an amphiphilic modifier. The mass ratio of modified carboxymethyl cellulose, ethanol, divinylbenzene, and benzoyl peroxide was 3:40:5:0.1.

[0073] Example 2

[0074] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 25 parts of single-component polyurethane adhesive, 40 parts of road waste concrete, 8 parts of reinforcing filler, 17 parts of manufactured sand, 7 parts of stone, 8 parts of mineral powder, 18 parts of cement, 0.8 parts of water-reducing agent, and 2.5 parts of curing agent.

[0075] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0076] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 350 r / min for 9 min to obtain the mixture;

[0077] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 35°C for 9 minutes to obtain polyurethane concrete.

[0078] The reinforcing filler is prepared by the following steps:

[0079] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 55°C for 25 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:15:8:13:3.

[0080] A2. Calcium chloride was added to deionized water and stirred at 75°C until completely dissolved. Chitosan-modified fly ash was added and stirred at 85°C for 2 hours. After cooling to room temperature, carbon dioxide was introduced and the mixture was stirred for 1.5 hours. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 20 minutes to obtain pretreated fly ash. The mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash was 1.5:53:10.

[0081] A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 55℃ for 25 min, filter, wash 3 times with deionized water, and dry in an oven at 100℃ for 5 min to obtain modified fly ash; the mass ratio of pretreated fly ash, deionized water and stearic acid is 10:55:2.5.

[0082] A4. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 5.5 h, and dry in a 105℃ constant temperature oven for 12 h to obtain the reinforced filler; the mass ratio of amphiphilic modifier, ethanol and modified fly ash is 3:65:10.

[0083] The amphiphilic modifier is prepared by the following steps:

[0084] B1. Carboxymethyl cellulose was added to ethanol and deionized water and stirred until homogeneous. γ-methacryloyloxypropyltrimethoxysilane was then added, and the mixture was stirred at 70°C for 1.5 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. It was then dried in a 70°C oven for 10 min to obtain modified carboxymethyl cellulose. The mass ratio of carboxymethyl cellulose, ethanol, deionized water, and γ-methacryloyloxypropyltrimethoxysilane was 2.5:30:15:0.8.

[0085] B2. Modified carboxymethyl cellulose was added to ethanol and stirred until homogeneous. Divinylbenzene and benzoyl peroxide were then added, and the mixture was stirred at 78°C for 1.5 h. The mixture was then dried at 90°C for 12 h to remove the organic solvent ethanol, thus obtaining an amphiphilic modifier. The mass ratio of modified carboxymethyl cellulose, ethanol, divinylbenzene, and benzoyl peroxide was 3.5:45:5.5:0.2.

[0086] Example 3

[0087] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 30 parts of single-component polyurethane adhesive, 42 parts of road waste concrete, 10 parts of reinforcing filler, 20 parts of manufactured sand, 8 parts of stone, 9 parts of mineral powder, 20 parts of cement, 1 part of water-reducing agent, and 3 parts of curing agent.

[0088] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0089] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 400 r / min for 10 min to obtain the mixture;

[0090] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 40°C for 10 minutes to obtain polyurethane concrete.

[0091] The reinforcing filler is prepared by the following steps:

[0092] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 60°C for 30 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:20:10:15:5.

[0093] A2. Calcium chloride was added to deionized water and stirred at 80°C until completely dissolved. Chitosan-modified fly ash was added and stirred at 90°C for 3 hours. After cooling to room temperature, carbon dioxide was introduced and the mixture was stirred for 2 hours. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 20 minutes to obtain pretreated fly ash. The mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash was 2:55:10.

[0094] A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 60℃ for 30 min, filter, wash 3 times with deionized water, and dry in an oven at 100℃ for 5 min to obtain modified fly ash; the mass ratio of pretreated fly ash, deionized water and stearic acid is 10:60:3.

[0095] A4. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 6 hours, and dry in a 105℃ constant temperature oven for 12 hours to obtain the reinforced filler; the mass ratio of amphiphilic modifier, ethanol and modified fly ash is 5:70:10.

[0096] The amphiphilic modifier is prepared by the following steps:

[0097] B1. Carboxymethyl cellulose was added to ethanol and deionized water and stirred until homogeneous. γ-methacryloyloxypropyltrimethoxysilane was then added and stirred at 75°C for 2 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain modified carboxymethyl cellulose. The mass ratio of carboxymethyl cellulose, ethanol, deionized water, and γ-methacryloyloxypropyltrimethoxysilane was 3:35:20:1.

[0098] B2. Modified carboxymethyl cellulose was added to ethanol and stirred until homogeneous. Divinylbenzene and benzoyl peroxide were then added, and the mixture was stirred at 80°C for 2 hours. The mixture was then dried at 90°C for 12 hours to remove the organic solvent ethanol, thus obtaining an amphiphilic modifier. The mass ratio of modified carboxymethyl cellulose, ethanol, divinylbenzene, and benzoyl peroxide was 3:50:6:0.3.

[0099] Comparative Example 1

[0100] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 30 parts of single-component polyurethane adhesive, 42 parts of road waste concrete, 10 parts of reinforcing filler, 20 parts of manufactured sand, 8 parts of stone, 9 parts of mineral powder, 20 parts of cement, 1 part of water-reducing agent, and 3 parts of curing agent.

[0101] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0102] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 400 r / min for 10 min to obtain the mixture;

[0103] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 40°C for 10 minutes to obtain polyurethane concrete.

[0104] The reinforcing filler is prepared by the following steps:

[0105] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 60°C for 30 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:20:10:15:5.

[0106] A2. Calcium chloride was added to deionized water and stirred at 80°C until completely dissolved. Chitosan-modified fly ash was added and stirred at 90°C for 3 hours. After cooling to room temperature, carbon dioxide was introduced and the mixture was stirred for 2 hours. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 20 minutes to obtain pretreated fly ash. The mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash was 2:55:10.

[0107] A3. Add the amphiphilic modifier to ethanol, stir evenly, add pretreated fly ash, let stand for 6 hours, and dry in a 105℃ constant temperature oven for 12 hours to obtain the reinforcing filler; the mass ratio of amphiphilic modifier, ethanol and pretreated fly ash is 5:70:10.

[0108] The amphiphilic modifier is prepared by the following steps:

[0109] B1. Carboxymethyl cellulose was added to ethanol and deionized water and stirred until homogeneous. γ-methacryloyloxypropyltrimethoxysilane was then added and stirred at 75°C for 2 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain modified carboxymethyl cellulose. The mass ratio of carboxymethyl cellulose, ethanol, deionized water, and γ-methacryloyloxypropyltrimethoxysilane was 3:35:20:1.

[0110] B2. Modified carboxymethyl cellulose was added to ethanol and stirred until homogeneous. Divinylbenzene and benzoyl peroxide were then added, and the mixture was stirred at 80°C for 2 hours. The mixture was then dried at 90°C for 12 hours to remove the organic solvent ethanol, thus obtaining an amphiphilic modifier. The mass ratio of modified carboxymethyl cellulose, ethanol, divinylbenzene, and benzoyl peroxide was 3:50:6:0.3.

[0111] Comparative Example 2

[0112] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 30 parts of single-component polyurethane adhesive, 42 parts of road waste concrete, 10 parts of reinforcing filler, 20 parts of manufactured sand, 8 parts of stone, 9 parts of mineral powder, 20 parts of cement, 1 part of water-reducing agent, and 3 parts of curing agent.

[0113] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0114] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 400 r / min for 10 min to obtain the mixture;

[0115] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 40°C for 10 minutes to obtain polyurethane concrete.

[0116] The reinforcing filler is prepared by the following steps:

[0117] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 60°C for 30 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:20:10:15:5.

[0118] A2. Chitosan-modified fly ash was added to deionized water and stirred evenly. Stearic acid was added and stirred at 60°C for 30 min. After filtration, the fly ash was washed three times with deionized water and dried in an oven at 100°C for 5 min to obtain modified fly ash. The mass ratio of pretreated fly ash, deionized water and stearic acid was 10:60:3.

[0119] A3. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 6 hours, and dry in a 105℃ constant temperature oven for 12 hours to obtain the reinforced filler; the mass ratio of amphiphilic modifier, ethanol and modified fly ash is 5:70:10.

[0120] The amphiphilic modifier is prepared by the following steps:

[0121] B1. Carboxymethyl cellulose was added to ethanol and deionized water and stirred until homogeneous. γ-methacryloyloxypropyltrimethoxysilane was then added and stirred at 75°C for 2 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain modified carboxymethyl cellulose. The mass ratio of carboxymethyl cellulose, ethanol, deionized water, and γ-methacryloyloxypropyltrimethoxysilane was 3:35:20:1.

[0122] B2. Modified carboxymethyl cellulose was added to ethanol and stirred until homogeneous. Divinylbenzene and benzoyl peroxide were then added, and the mixture was stirred at 80°C for 2 hours. The mixture was then dried at 90°C for 12 hours to remove the organic solvent ethanol, thus obtaining an amphiphilic modifier. The mass ratio of modified carboxymethyl cellulose, ethanol, divinylbenzene, and benzoyl peroxide was 3:50:6:0.3.

[0123] Comparative Example 3

[0124] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 30 parts of single-component polyurethane adhesive, 42 parts of road waste concrete, 10 parts of reinforcing filler, 20 parts of manufactured sand, 8 parts of stone, 9 parts of mineral powder, 20 parts of cement, 1 part of water-reducing agent, and 3 parts of curing agent.

[0125] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0126] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 400 r / min for 10 min to obtain the mixture;

[0127] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 40°C for 10 minutes to obtain polyurethane concrete.

[0128] The reinforcing filler is prepared by the following steps:

[0129] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 60°C for 30 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:20:10:15:5.

[0130] A2. Calcium chloride was added to deionized water and stirred at 80°C until completely dissolved. Chitosan-modified fly ash was added and stirred at 90°C for 3 hours. After cooling to room temperature, carbon dioxide was introduced and the mixture was stirred for 2 hours. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 20 minutes to obtain pretreated fly ash. The mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash was 2:55:10.

[0131] A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 60℃ for 30 min, filter, wash 3 times with deionized water, and dry in an oven at 100℃ for 5 min to obtain modified fly ash; the mass ratio of pretreated fly ash, deionized water and stearic acid is 10:60:3.

[0132] A4. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 6 hours, and dry in a 105℃ constant temperature oven for 12 hours to obtain the reinforced filler; the mass ratio of amphiphilic modifier, ethanol and modified fly ash is 5:70:10.

[0133] The amphiphilic modifier is prepared by the following steps:

[0134] Carboxymethyl cellulose was added to ethanol and stirred until homogeneous. Divinylbenzene and benzoyl peroxide were then added, and the mixture was stirred at 80°C for 2 hours. The mixture was then dried at 90°C for 12 hours to remove the organic solvent ethanol, thus obtaining an amphiphilic modifier. The mass ratio of carboxymethyl cellulose, ethanol, divinylbenzene, and benzoyl peroxide was 3:50:6:0.3.

[0135] Comparative Example 4

[0136] A polyurethane concrete based on solid waste materials comprises the following raw materials in parts by weight: 30 parts of single-component polyurethane adhesive, 42 parts of road waste concrete, 10 parts of reinforcing filler, 20 parts of manufactured sand, 8 parts of stone, 9 parts of mineral powder, 20 parts of cement, 1 part of water-reducing agent, and 3 parts of curing agent.

[0137] A method for preparing polyurethane concrete based on solid waste materials includes the following preparation steps:

[0138] S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 400 r / min for 10 min to obtain the mixture;

[0139] S2. Mix the mixture, water-reducing agent and curing agent, and stir at 40°C for 10 minutes to obtain polyurethane concrete.

[0140] The reinforcing filler is prepared by the following steps:

[0141] A1. Fly ash, acetone, and sodium hydroxide were mixed and stirred at 60°C for 30 min. Epichlorohydrin was added, and stirring was continued for 1 h. Chitosan solution was added, and stirring was continued for 1 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain chitosan-modified fly ash. The mass ratio of fly ash, acetone, sodium hydroxide, epichlorohydrin, and chitosan solution was 10:20:10:15:5.

[0142] A2. Calcium chloride was added to deionized water and stirred at 80°C until completely dissolved. Chitosan-modified fly ash was added and stirred at 90°C for 3 hours. After cooling to room temperature, carbon dioxide was introduced and the mixture was stirred for 2 hours. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 20 minutes to obtain pretreated fly ash. The mass ratio of calcium chloride, deionized water, and chitosan-modified fly ash was 2:55:10.

[0143] A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 60℃ for 30 min, filter, wash 3 times with deionized water, and dry in an oven at 100℃ for 5 min to obtain modified fly ash; the mass ratio of pretreated fly ash, deionized water and stearic acid is 10:60:3.

[0144] A4. Add modified carboxymethyl cellulose to ethanol, stir evenly, add modified fly ash, let stand for 6 hours, and dry in a constant temperature oven at 105℃ for 12 hours to obtain the reinforcing filler; the mass ratio of modified carboxymethyl cellulose, ethanol and modified fly ash is 5:70:10.

[0145] Modified carboxymethyl cellulose is prepared by the following steps:

[0146] Carboxymethyl cellulose was added to ethanol and deionized water and stirred until homogeneous. γ-methacryloyloxypropyltrimethoxysilane was then added, and the mixture was stirred at 75°C for 2 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. Finally, it was dried in an oven at 70°C for 10 minutes to obtain modified carboxymethyl cellulose. The mass ratio of carboxymethyl cellulose, ethanol, deionized water, and γ-methacryloyloxypropyltrimethoxysilane was 3:35:20:1.

[0147] The performance of the polyurethane concrete prepared in Examples 1-3 and Comparative Examples 1-4 was then tested.

[0148] Mechanical performance testing: The recycled waste polyurethane concrete prepared above was made into cubic specimens with a side length of 150 mm. After curing at an ambient temperature of 25°C for 28 days, its compressive strength, flexural strength and tensile strength were tested according to the standard GB / T50081-2019 for testing physical and mechanical properties of concrete.

[0149] Concrete porosity testing: The recycled waste polyurethane concrete prepared above is made into a standard block. After curing for 28 days, the natural volume V1 of the standard block is measured. Then the standard block is ground into powder, and the volume V2 of the powder is measured by the drainage method. Porosity = (V1-V2) / V1.

[0150] Impermeability test: The test was conducted in accordance with GB18445-2012 standard "Cement-based penetrating crystalline waterproofing materials (waterproofing agents)".

[0151] The test results are shown in Table 1 below.

[0152] Table 1. Performance testing of polyurethane concrete prepared in Examples 1-3 and Comparative Examples 1-4

[0153]

[0154] As shown in Table 1, the polyurethane concrete prepared in Examples 1-3 exhibits good mechanical strength, high density, and excellent impermeability. In Comparative Example 1, replacing the modified fly ash with reinforcing filler prepared from pretreated fly ash resulted in a decrease in the mechanical properties of the polyurethane concrete. This demonstrates that introducing calcium stearate into the pores of the pretreated fly ash improves the hydrophobicity and impermeability of the concrete. Furthermore, the intertwined stearate chains form a cross-linked network structure, which prevents the migration and precipitation of calcium carbonate, enhancing its stability within the pretreated fly ash.

[0155] In Comparative Example 2, when pretreated fly ash was replaced with chitosan-modified fly ash to prepare reinforcing filler, the mechanical properties of the polyurethane concrete decreased. This demonstrates that calcium carbonate is generated in situ in the pores of the chitosan-modified fly ash, which can block the pore structure of the fly ash, effectively reduce the porosity of the fly ash, improve its impermeability, and prevent the fly ash from easily absorbing water, thus avoiding a decrease in the mechanical strength of the concrete.

[0156] In Comparative Example 3, when the modified carboxymethyl cellulose was replaced with a reinforcing filler prepared from carboxymethyl cellulose and added to polyurethane concrete, its mechanical properties decreased. This demonstrates that grafting a silane coupling agent onto carboxymethyl cellulose is beneficial for the grafting of carboxymethyl cellulose onto divinylbenzene polymer to form an amphiphilic modifier, which coats the surface of pretreated fly ash, imparts excellent adhesion to fly ash, and improves the bonding force between fly ash and concrete filler.

[0157] In Comparative Example 4, when the amphiphilic modifier was replaced with a reinforcing filler prepared from modified carboxymethyl cellulose and added to polyurethane concrete, its mechanical properties decreased. This demonstrates that the amphiphilic modifier has a porous structure, which coats the surface of the modified fly ash and can be compounded with calcium stearate to further adsorb and fix the calcium carbonate component synthesized in the modified fly ash, thereby further improving the stability of calcium carbonate in the modified fly ash. Furthermore, the carbon chain structure contained in the divinylbenzene polymer can intercalate into the gaps in the concrete, enhancing the compatibility of the modified fly ash in the concrete slurry and improving the density and mechanical properties of the concrete.

[0158] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0159] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A polyurethane concrete based on solid waste materials, characterized in that, The raw materials include the following parts by weight: 20-30 parts of single-component polyurethane adhesive, 38-42 parts of road waste concrete, 5-10 parts of reinforcing filler, 15-20 parts of manufactured sand, 6-8 parts of stone, 6-9 parts of mineral powder, 15-20 parts of cement, 0.5-1 part of water-reducing agent, and 2-3 parts of curing agent. The reinforcing filler is prepared by the following steps: A1. Mix fly ash, acetone and sodium hydroxide, stir at 50-60℃ for 20-30 min, add to epichlorohydrin, stir, add chitosan solution, continue stirring, filter, wash and dry to obtain chitosan modified fly ash; A2. Add calcium chloride to deionized water and stir at 70-80℃ until completely dissolved. Add chitosan-modified fly ash and stir at 80-90℃ for 1-3 hours. Cool to room temperature, introduce carbon dioxide, and stir for 1-2 hours. After filtration, washing, and drying, pretreated fly ash is obtained. A3. Add the pretreated fly ash to deionized water, stir evenly, add stearic acid, stir and react at 50-60℃ for 20-30 minutes, filter, wash and dry to obtain modified fly ash; A4. Add the amphiphilic modifier to ethanol, stir evenly, add modified fly ash, let stand for 5-6 hours, and dry to obtain the reinforced filler; The chitosan solution is prepared by mixing chitosan and acetic acid in a mass ratio of (2-3):(50-60); The amphiphilic modifier is prepared by the following steps: B1. Add carboxymethyl cellulose to ethanol and deionized water, stir well, add silane coupling agent, stir and react at 65-75℃ for 1-2 hours, cool to room temperature, filter, wash and dry to obtain modified carboxymethyl cellulose. B2. Add modified carboxymethyl cellulose to ethanol, stir until homogeneous, add divinylbenzene and benzoyl peroxide, stir and react at 75-80℃ for 1-2 hours, dry to remove the organic solvent ethanol, and obtain the amphiphilic modifier.

2. The polyurethane concrete based on solid waste materials according to claim 1, characterized in that, The manufactured sand has a particle size of 4-4.5 mm and an apparent density of 2500-2600 kg / m³.

3. The polyurethane concrete based on solid waste materials according to claim 1, characterized in that, The stone material is selected from any one of basalt gravel, limestone, and natural sand.

4. The polyurethane concrete based on solid waste materials according to claim 1, characterized in that, The mineral powder is S95 grade slag powder with a density of 2.5-3.9 g / cm³. 3 Specific surface area is 445-460 m² 2 / kg.

5. The polyurethane concrete based on solid waste materials according to claim 1, characterized in that, The curing agent is a mixture of ethylene glycol, petroleum ether, water and cumene hydrogen peroxide at room temperature; the mass ratio of ethylene glycol, petroleum ether, water and cumene hydrogen peroxide is 3-4:2-3:2-4:1-2.

6. The polyurethane concrete based on solid waste materials according to claim 1, characterized in that, The cement is grade 42.5 low-alkalinity sulfoaluminate cement.

7. A method for preparing polyurethane concrete based on solid waste materials as described in any one of claims 1-6, characterized in that, The preparation steps include the following: S1. Mix the single-component polyurethane adhesive, road waste concrete, reinforcing filler, manufactured sand, stone, mineral powder and cement, and stir at a speed of 300-400 r / min for 8-10 min to obtain the mixture; S2. Mix the mixture, water-reducing agent and curing agent, and stir at 30-40℃ for 8-10 minutes to obtain polyurethane concrete.

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