A method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste

Abstract

The present invention belongs to the field of building material production technology, specifically a method for producing recycled concrete using construction solid waste and unburned light aggregate waste. The specific steps are as follows: Step 1: Collect the solid waste generated by the construction, and pick out the debris inside the construction solid waste through magnetic separation and debris sorting. When the construction solid waste and unburned light aggregate are processed into blocks, the application pours them into the interior of a negative pressure bin for strengthening, thereby making them harder. In the later use process, the compression resistance and tensile strength are stronger. During the preparation process, antifreeze-type water reducers, regulators, rust inhibitors and expansion agents are added to improve the fluidity and pumpability of the concrete, thereby improving construction efficiency and quality, enhancing the durability of the concrete, and improving its ability to resist chemical corrosion and physical damage. The density, color and volume stability of the concrete can also be adjusted to meet the needs of specific projects.

Description

Technical Field

[0001] The present invention belongs to the technical field of building material production, and in particular relates to a method for producing recycled concrete by utilizing construction solid waste and unburned lightweight aggregate waste. Background Art

[0002] Concrete, abbreviated as "concrete," is a general term for engineering composite materials composed of aggregates bonded together by a cementitious material. Concrete, commonly referred to as cement as the binder, sand and stone as aggregates, and water (which may contain admixtures and additives) mixed in a specific proportion, is widely used in civil engineering. Cement concrete, also known as ordinary concrete, is widely used in civil engineering.

[0003] At present, with the continuous expansion of the scale of the construction industry, the demand for concrete is increasing. Therefore, in order to save certain resources, the solid waste and lightweight bone waste generated by construction will be recycled and processed again to produce concrete, so as to achieve the purpose of effectively saving resources.

[0004] Solid construction waste generally refers to solid waste construction materials. Solid waste construction materials refer to various solid wastes such as coal gangue, fly ash, coal slag, blast furnace slag, steel slag, etc., which have the components and properties required for construction materials and can be used to make construction materials; lightweight aggregate is made of light coarse aggregate, light fine aggregate or ordinary fine aggregate, cement, water, admixtures and admixtures, and can be used as concrete. Its apparent density is not more than 1950kg / m 3 It is often named after the type of lightweight aggregate used, such as pumice concrete, fly ash ceramsite concrete, clay ceramsite concrete, shale ceramsite concrete, expanded perlite concrete, etc. Lightweight aggregates include natural lightweight aggregates: pumice, volcanic slag; industrial waste: fly ash ceramsite, expanded slag beads; artificial lightweight aggregates: shale ceramsite, clay ceramsite, expanded perlite.

[0005] The current methods of recycled concrete mainly rely solely on construction solid waste or solely on lightweight bone waste. The two cannot be effectively mixed and processed to produce recycled concrete. In addition, the concrete prepared by the current methods is of low quality. During later use, the density is poor, the heat and cold resistance is limited, and the compressive strength and tensile strength are weak, which seriously affects the safety of later buildings.

[0006] To this end, a method for producing recycled concrete from construction solid waste and unburned lightweight aggregate waste is proposed to solve the above-mentioned problems. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste, the specific steps are as follows:

[0010] Step 1: Collect the solid waste generated by construction, sort out the debris inside the construction solid waste through magnetic separation and debris sorting, pour the remaining construction solid waste into the crushing device, and crush the cement blocks, bricks, stones and other solid waste into 10-30mm blocks through multi-stage crushing. Then, the crushed blocks are transported to the inside of the cleaning device through the conveying device for cleaning. After cleaning, they are transported to the corresponding location and stored for use;

[0011] Step 2: Collect the light aggregate waste and classify it after collection to ensure the purity and quality of the waste. Crush the classified light aggregate waste into blocks. After crushing, use a screening device to screen it to obtain aggregates of different particle sizes. Wash the crushed and screened aggregates and transport them to the corresponding location for standby use after washing.

[0012] Step 3: Mix the prepared construction solid waste block material and lightweight aggregate waste block material with each other, pour the mixture into the interior of the negative pressure bin, close the inlet and outlet channels of the negative pressure bin, set an air pump inside the negative pressure bin, extract the air inside the negative pressure bin by the air pump, so that a negative pressure is formed inside the negative pressure bin, and the negative pressure value in the negative pressure bin is controlled between -5KPa and -85KPa. During the negative pressure process, the mixture inside the negative pressure bin is continuously tumbled and stirred, the tumbling and stirring speed is controlled at 30-40 revolutions per minute, the pressure holding time is controlled at 20-30 minutes, and the internal mixture is heated in combination with infrared heat radiation during the pressure holding process. The heating temperature is controlled at 200-300 degrees Celsius and the heating time is 30-40 minutes to obtain recycled aggregate;

[0013] Step 4: Take 250-300 parts of mineral admixture, 325-335 parts of cement, 12-14 parts of antifreeze type water reducer, 10-12 parts of regulator, 6-8 parts of rust inhibitor, 12-14 parts of expansion agent, 80-100 parts of composite fiber, and 450-550 parts of water in parts by weight and pour them into the interior of the mixing device, control the stirring speed of the mixing device to 80-100 rpm, and when it is stirred into a viscous state, take 800-1000 parts of recycled aggregate and pour it therein, continue stirring at the same speed for 30-40 minutes to obtain concrete.

[0014] Preferably, the magnetic separation in step one is to pick out metal objects in construction solid waste, and the debris sorting is to pick out lighter or smaller impurities in construction solid waste; the multi-stage crushing includes primary crushing, secondary crushing, and tertiary crushing, the primary crushing is a jaw crusher, the secondary crushing is a cone crusher, and the tertiary crushing is an impact crusher; the cleaning device is to wash the lumps to wash away the large amount of dust mixed inside them.

[0015] Preferably, the mineral admixture includes fly ash, mineral powder and silicon powder, and the mass ratio of the three is 1:2:1.

[0016] Preferably, the conditioning agent is a mixture of soda ash and borax.

[0017] Preferably, the cement is one of ordinary Portland cement, aluminate cement, composite Portland cement, sulfate-resistant Portland cement and rapid-hardening Portland cement.

[0018] Preferably, the composite fiber is one of steel fiber, polyacrylonitrile fiber and glass fiber.

[0019] Preferably, in parts by weight, the specific raw material components of the recycled concrete include: 250 parts of mineral admixture, 325 parts of cement, 12 parts of antifreeze-type water reducer, 10 parts of regulator, 6 parts of rust inhibitor, 12 parts of expansion agent, 80 parts of composite fiber, 450 parts of water and 800 parts of recycled aggregate.

[0020] Preferably, in parts by weight, the specific raw material components of the recycled concrete include: 275 parts of mineral admixture, 330 parts of cement, 13 parts of antifreeze-type water reducer, 11 parts of regulator, 7 parts of rust inhibitor, 13 parts of expansion agent, 90 parts of composite fiber, 500 parts of water and 900 parts of recycled aggregate.

[0021] Preferably, in parts by weight, the specific raw material components of the recycled concrete include: 300 parts of mineral admixture, 335 parts of cement, 14 parts of antifreeze-type water reducer, 12 parts of regulator, 8 parts of rust inhibitor, 14 parts of expansion agent, 100 parts of composite fiber, 550 parts of water and 1000 parts of recycled aggregate.

[0022] Preferably, the antifreeze-type water-reducing agent is prepared by the following steps:

[0023] S1. Add terephthalic acid, triethylamine and NaOH aqueous solution (mass fraction 30%) to a dry three-necked flask equipped with a stirring device, a condensing reflux device and a nitrogen conduit, and introduce nitrogen for 10 minutes. Then, add 3-aminopropylene ethanol solution and DIC (N,N-diisopropylcarbodiimide, condensing agent). After the addition is complete, stir and react at room temperature under N2 protection for 3 hours. After the reaction is completed, extract with chloroform three times, take the organic layer, dry it over anhydrous magnesium sulfate, filter, and finally rotary evaporate (to remove chloroform and ethanol) to obtain an intermediate product;

[0024] The ratio of terephthalic acid, triethylamine, 3-aminopropylene and DIC is 0.05 mol:5.1 g:0.05 mol:6.3 g;

[0025] The concentration of 3-aminopropylene dissolved in ethanol is 2.85 g / 30 mL;

[0026] Under the action of triethylamine and DIC, the -COOH on the terephthalic acid molecule undergoes an amidation reaction with the -NH2 on the 3-aminopropylene molecule, and by controlling the molar ratio of the two to be 1:1, an intermediate product is obtained. The reaction process is as follows:

[0027]

[0028] S2. Add the intermediate product and hydroxy silicone oil to a three-necked flask, stir and heat, control the temperature in the three-necked flask between 160-180° C., collect the by-product water through a condenser, stop heating when the water output reaches the theoretical amount and no water is output for 10 minutes, cool to room temperature, and obtain a modifier;

[0029] The relative molecular mass of the hydroxy silicone oil is 500; the molar ratio of the intermediate product to the hydroxy silicone oil is 1:1;

[0030] The -COOH on the intermediate product molecule undergoes an esterification reaction with the terminal -OH of the hydroxy silicone oil to obtain a modifier. The process is as follows:

[0031]

[0032] S3. Mix hydroxyethyl acrylate and the modifier evenly, transfer 2 / 3 to a four-necked flask, start stirring, transfer 2-methylprop-2-enyl polyethylene glycol ether to the flask, then add sodium methacrylate sulfonate, and transfer the remaining 1 / 3 of the mixture to a four-necked flask. Adjust the temperature to 28-32°C, keep the temperature constant for 10 minutes, then slowly add the sodium formaldehyde sulfoxylate solution to the four-necked flask, and simultaneously add an aqueous solution of acrylic acid and an aqueous solution of tert-butyl hydroperoxide. After the addition is complete, keep the temperature for 90 minutes, and neutralize with liquid caustic soda to a pH of 5-7 to obtain a water reducer.

[0033] The relative molecular mass of 2-methylprop-2-enyl polyethylene glycol ether is 2400; the molar ratio of acrylic acid to 2-methylprop-2-enyl polyethylene glycol ether is 7.5:1; the amounts of tert-butyl hydroperoxide, sodium formaldehyde sulfoxylate, sodium methacrylate sulfonate, modifier, and hydroxyethyl acrylate are 0.6%, 0.2%, 1.6%, 0.4%, and 0.1% of the mass of 2-methylprop-2-enyl polyethylene glycol ether, respectively.

[0034] By introducing hydrophobic groups such as hydroxyl groups and ester groups into the water reducer through the modifier, the adsorption of the water reducer to materials such as cement is weakened, which is manifested macroscopically as the improvement of the fluidity retention of the net slurry. In addition, the addition of the modifier can also introduce ortho groups, methyl groups and other groups. These groups occupy a larger spatial position, so that the stereo effect can be fully exerted, thereby improving the slump retention performance of the water reducer. It should be further explained that the main chain of the modifier is silane, and the alkoxy groups in the silane molecules are hydrolyzed to produce siloxane groups, which act as anchoring groups on the cement surface, resulting in the silane molecules being fully adsorbed on the cement particles, and the siloxane chains provide a spatial repulsion effect between the cement particles in some way, so that it has a better dispersion effect on the cement slurry, making the slurry more stable.

[0035] Beneficial effects of the present invention:

[0036] The main materials of this application are construction solid waste and unburned light aggregate, which recycles waste and saves production resources. When processing construction solid waste and unburned light aggregate into blocks, this application pours them into the interior of a negative pressure bin for strengthening, thereby making them harder. In the later use process, the compression and tensile strength are stronger. During the preparation process, antifreeze-type water reducers, regulators, pumping agents, rust inhibitors and expansion agents are added to improve the fluidity and pumpability of concrete, thereby improving construction efficiency and quality, enhancing the durability of concrete, and improving its ability to resist chemical corrosion and physical damage. The density, color and volume stability of the concrete can also be adjusted to meet the needs of specific projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below with reference to the accompanying drawings.

[0038] Figure 1 The figure is a flow chart of the preparation steps of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] A method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste, such as Figure 1 The specific steps are as follows:

[0041] Step 1: Collect the solid waste generated by construction, sort out the debris inside the construction solid waste through magnetic separation and debris sorting, pour the remaining construction solid waste into the crushing device, and crush the cement blocks, bricks, stones and other solid waste into 10-30mm blocks through multi-stage crushing. Then, the crushed blocks are transported to the inside of the cleaning device through the conveying device for cleaning. After cleaning, they are transported to the corresponding location and stored for use;

[0042] Impact of solid waste on concrete performance:

[0043] Mechanical properties: When solid waste partially replaces cement or aggregate, it will affect the mechanical properties of concrete. If the added solid waste composition is appropriate, the strength and crack resistance of concrete will be improved.

[0044] Microscopic effects: Solid waste contains various chemical components that may affect the microscopic composition of cement paste and its chemical reactions, thereby affecting concrete and its cost.

[0045] Durability: Some solid wastes can react with cement stone in concrete, causing the calcium limestone in the concrete to react with the cement stone and increase the excess of calcium limestone. These reactions may damage the durability of the concrete.

[0046] When selecting solid waste, the mixture should be reasonably matched. The proportion of solid waste in concrete preparation should be determined through experiments to achieve the best economic effect. Pay attention to the properties of solid waste, especially those that are perishable, flammable, explosive, and toxic. Strengthen concrete quality control. For solid waste concrete, the quality control of concrete should be done well to ensure that the concrete has good mechanical properties and durability.

[0047] Step 2: Collect the light aggregate waste and classify it after collection to ensure the purity and quality of the waste. Crush the classified light aggregate waste into blocks. After crushing, use a screening device to screen it to obtain aggregates of different particle sizes. Wash the crushed and screened aggregates and transport them to the corresponding location for standby use after washing.

[0048] Light aggregate can be divided into light coarse aggregate and light fine aggregate. Any aggregate with a particle size greater than 4.75 mm and a bulk density less than 1100 kg / m 3 Lightweight aggregate is called light coarse aggregate; any aggregate with a particle size not exceeding 4.75 mm and a bulk density less than 1200 kg / m 3 Lightweight aggregate. It is called light fine aggregate (or light sand);

[0049] According to the provisions of "Light Aggregate and Its Test Methods Part 1: Light Aggregate" (GB / T17431.1-2010), light aggregate can be divided into: industrial waste residue light aggregate, such as fly ash ceramsite, spontaneous combustion coal gangue, expanded slag beads, coal slag and light sand; natural light aggregate, such as pumice, volcanic slag and light sand; artificial light aggregate, such as shale ceramsite, clay ceramsite, expanded perlite and light sand. The technical requirements for light aggregate mainly include four items: bulk density, strength, particle grading and water absorption.

[0050] The mix design of lightweight aggregate concrete should meet the requirements of strength, workability, durability, economy, etc.

[0051] The water-binder ratio of lightweight aggregate concrete is expressed as net water-binder ratio, which refers to the ratio of net water consumption, excluding the water absorption of lightweight aggregate in 1 hour, to the amount of cementitious materials used. When preparing fully lightweight concrete, it is allowed to be expressed as total water-binder ratio, which refers to the ratio of total water consumption, including the water absorption of lightweight aggregate in 1 hour, to the amount of cementitious materials used.

[0052] Lightweight aggregate tends to float and is difficult to mix evenly, so a forced mixer should be used, and the mixing time should be slightly longer than that of ordinary concrete.

[0053] In order to reduce the slump loss and segregation of concrete mixture, the transportation distance should be shortened as much as possible. The duration of the mixture from the unloading of the mixer to the pouring of the mold should not exceed 45 minutes.

[0054] In order to reduce the floating of lightweight aggregate, it is best to use pressurized vibration during construction. The vibration time should be based on the compaction and should not be too long.

[0055] After pouring and forming, it should be covered and watered in time to prevent the surface from losing water too quickly and causing network cracks. The curing time should be no less than 7-14 days depending on the type of cementitious material.

[0056] When lightweight aggregate concrete is constructed in seasons with temperatures above 5°C, the light coarse aggregate can be pre-wetted according to project needs. This will ensure that the workability and water-cement ratio of the mixture are relatively stable. The pre-wetting time can be determined based on the outside temperature and the natural moisture content of the aggregate. Generally, the aggregate should be pre-wetted by sprinkling water half a day or a day in advance, and then the water should be drained before feeding.

[0057] Step 3: Mix the prepared construction solid waste block material and lightweight aggregate waste block material with each other, pour the mixture into the interior of the negative pressure bin, close the inlet and outlet channels of the negative pressure bin, set an air pump inside the negative pressure bin, extract the air inside the negative pressure bin by the air pump, so that a negative pressure is formed inside the negative pressure bin, and the negative pressure value in the negative pressure bin is controlled between -5KPa and -85KPa. During the negative pressure process, the mixture inside the negative pressure bin is continuously tumbled and stirred, the tumbling and stirring speed is controlled at 30-40 revolutions per minute, the pressure holding time is controlled at 20-30 minutes, and the internal mixture is heated in combination with infrared heat radiation during the pressure holding process. The heating temperature is controlled at 200-300 degrees Celsius and the heating time is 30-40 minutes to obtain recycled aggregate;

[0058] Step 4: Take 250-300 parts of mineral admixture, 325-335 parts of cement, 12-14 parts of antifreeze type water reducer, 10-12 parts of regulator, 6-8 parts of rust inhibitor, 12-14 parts of expansion agent, 80-100 parts of composite fiber, and 450-550 parts of water and pour them into the interior of the mixing device. Control the stirring speed of the mixing device to 80-100 rpm. When it is stirred into a viscous state, take 800-1000 parts of recycled aggregate and pour it therein. Continue stirring at the same speed for 30-40 minutes to obtain concrete.

[0059] Example 1

[0060] Preparation of antifreeze water reducing agent:

[0061] S1. Add terephthalic acid, triethylamine and NaOH aqueous solution (mass fraction 30%) to a dry three-necked flask equipped with a stirring device, a condensing reflux device and a nitrogen conduit, and introduce nitrogen for 10 minutes. Then, add 3-aminopropylene ethanol solution and DIC (N, N-diisopropylcarbodiimide, condensing agent). After the addition is complete, stir and react at room temperature under N2 protection for 3 hours. After the reaction is completed, extract with chloroform three times, take the organic layer, dry it over anhydrous magnesium sulfate, filter, and finally rotary evaporate (to remove chloroform and ethanol) to obtain an intermediate product; the ratio of terephthalic acid, triethylamine, 3-aminopropylene and DIC is 0.05 mol:5.1 g:0.05 mol:6.3 g; the concentration of 3-aminopropylene ethanol solution is 2.85 g / 30 mL;

[0062] S2. Add the intermediate product and hydroxy silicone oil to a three-necked flask, stir and heat, control the temperature in the three-necked flask between 160-180° C., collect the by-product water through a condenser, stop heating when the water output reaches the theoretical amount and no water is output for 10 minutes, cool to room temperature, and obtain a modifier; the relative molecular mass of the hydroxy silicone oil is 500; and the molar ratio of the intermediate product to the hydroxy silicone oil is 1:1;

[0063] S3. Mix hydroxyethyl acrylate and modifier evenly, transfer 2 / 3 to a four-necked flask, start stirring, transfer 2-methylprop-2-enyl polyethylene glycol ether to the flask, then add sodium methacrylate sulfonate, and transfer the remaining 1 / 3 of the mixture to a four-necked flask, adjust the temperature to 28-32°C, keep the temperature constant for 10 minutes, then slowly add sodium formaldehyde sulfoxylate solution to the four-necked flask, and simultaneously add acrylic acid aqueous solution and tert-butyl hydroperoxide aqueous solution, and keep the temperature for 90 minutes after the addition is complete. in, and liquid alkali is neutralized to a pH value of 5-7 to obtain a water reducer; the relative molecular mass of 2-methylprop-2-enyl polyethylene glycol ether is 2400; the molar ratio of acrylic acid to 2-methylprop-2-enyl polyethylene glycol ether is 7.5:1; the amounts of tert-butyl hydroperoxide, sodium formaldehyde sulfoxylate, sodium methacrylate, modifier, and hydroxyethyl acrylate are 0.6%, 0.2%, 1.6%, 0.4%, and 0.1% of the mass of 2-methylprop-2-enyl polyethylene glycol ether, respectively.

[0064] Example 2

[0065] Step 1: Collect the solid waste generated by construction, sort out the debris inside the construction solid waste through magnetic separation and debris sorting, pour the remaining construction solid waste into the crushing device, and crush the cement blocks, bricks, stones and other solid waste into 10mm blocks through multi-stage crushing. Then, the crushed blocks are transported to the inside of the cleaning device through the conveying device for cleaning. After cleaning, they are transported to the corresponding location and placed for standby;

[0066] Step 2: Collect the light aggregate waste and classify it after collection to ensure the purity and quality of the waste. Crush the classified light aggregate waste into blocks. After crushing, use a screening device to screen it to obtain aggregates of different particle sizes. Wash the crushed and screened aggregates and transport them to the corresponding location for standby use after washing.

[0067] Step 3: Mix the prepared construction solid waste block material and lightweight aggregate waste block material with each other, pour the mixture into the interior of the negative pressure bin, close the inlet and outlet channels of the negative pressure bin, set an air pump inside the negative pressure bin, extract the air inside the negative pressure bin by the air pump, so that a negative pressure is formed inside the negative pressure bin, and the negative pressure value in the negative pressure bin is controlled between -5KPa and -85KPa. During the negative pressure process, the mixture inside the negative pressure bin is continuously tumbled and stirred, the tumbling and stirring speed is controlled at 30 revolutions per minute, the pressure holding time is controlled at 20 minutes, and the internal mixture is heated in combination with infrared heat radiation during the pressure holding process, the heating temperature is controlled at 200 degrees Celsius, and the heating time is 30 minutes to obtain recycled aggregate;

[0068] Step 4: Take 250 parts of mineral admixture, 325 parts of cement, 12 parts of antifreeze type water reducer, 10 parts of regulator, 6 parts of phosphate rust inhibitor, 12 parts of calcium sulfoaluminate (expansion agent), 80 parts of composite fiber, and 450 parts of water in parts by weight and pour them into the interior of the mixing device, control the stirring speed of the mixing device to 80 rpm, and when it is stirred into a viscous state, take 800 parts of recycled aggregate and pour it therein, continue stirring at the same speed for 30 minutes to obtain concrete;

[0069] Example 3

[0070] Step 1: Collect the solid waste generated by construction, sort out the debris inside the construction solid waste through magnetic separation and debris sorting, pour the remaining construction solid waste into the crushing device, and crush the cement blocks, bricks, stones and other solid waste into 20mm blocks through multi-stage crushing. Then, the crushed blocks are transported to the inside of the cleaning device through the conveying device for cleaning. After cleaning, they are transported to the corresponding location and placed for standby;

[0071] Step 2: Collect the light aggregate waste and classify it after collection to ensure the purity and quality of the waste. Crush the classified light aggregate waste into blocks. After crushing, use a screening device to screen it to obtain aggregates of different particle sizes. Wash the crushed and screened aggregates and transport them to the corresponding location for standby use after washing.

[0072] Step 3: Mix the prepared construction solid waste block material and lightweight aggregate waste block material with each other, pour the mixture into the interior of the negative pressure bin, close the inlet and outlet channels of the negative pressure bin, set an air pump inside the negative pressure bin, extract the air inside the negative pressure bin by the air pump, so that a negative pressure is formed inside the negative pressure bin, and the negative pressure value in the negative pressure bin is controlled between -5KPa and -85KPa. During the negative pressure process, the mixture inside the negative pressure bin is continuously tumbled and stirred, the tumbling and stirring speed is controlled at 35 revolutions per minute, the pressure holding time is controlled at 25 minutes, and the internal mixture is heated in combination with infrared heat radiation during the pressure holding process, the heating temperature is controlled at 250 degrees Celsius, and the heating time is 35 minutes to obtain recycled aggregate;

[0073] Step 4: Take 275 parts of mineral admixture, 330 parts of cement, 13 parts of antifreeze type water reducer, 11 parts of regulator, 7 parts of phosphate rust inhibitor, 13 parts of calcium sulfoaluminate (expansion agent), 90 parts of composite fiber, and 500 parts of water in parts by weight and pour them into the interior of the mixing device. Control the stirring speed of the mixing device to 90 rpm. When it is stirred into a viscous state, take 900 parts of recycled aggregate and pour it therein. Continue stirring at the same speed for 35 minutes to obtain concrete;

[0074] Example 4

[0075] Step 1: Collect the solid waste generated by construction, sort out the debris inside the construction solid waste through magnetic separation and debris sorting, pour the remaining construction solid waste into the crushing device, and crush the cement blocks, bricks, stones and other solid waste into 30mm blocks through multi-stage crushing. Then, the crushed blocks are transported to the inside of the cleaning device through the conveying device for cleaning. After cleaning, they are transported to the corresponding location and placed for standby;

[0076] Step 2: Collect the light aggregate waste and classify it after collection to ensure the purity and quality of the waste. Crush the classified light aggregate waste into blocks. After crushing, use a screening device to screen it to obtain aggregates of different particle sizes. Wash the crushed and screened aggregates and transport them to the corresponding location for standby use after washing.

[0077] Step 3: Mix the prepared construction solid waste block material and lightweight aggregate waste block material with each other, pour the mixture into the interior of the negative pressure bin, close the inlet and outlet channels of the negative pressure bin, set an air pump inside the negative pressure bin, extract the air inside the negative pressure bin by the air pump, so that a negative pressure is formed inside the negative pressure bin, and the negative pressure value in the negative pressure bin is controlled between -5KPa and -85KPa. During the negative pressure process, the mixture inside the negative pressure bin is continuously tumbled and stirred, the tumbling and stirring speed is controlled at 40 revolutions per minute, the pressure holding time is controlled at 30 minutes, and the internal mixture is heated in combination with infrared heat radiation during the pressure holding process, the heating temperature is controlled at 300 degrees Celsius, and the heating time is 40 minutes to obtain recycled aggregate;

[0078] Step 4: Take 300 parts of mineral admixture, 335 parts of cement, 14 parts of antifreeze-type water reducer, 12 parts of regulator, 8 parts of phosphate rust inhibitor, 14 parts of calcium sulfoaluminate (expansion agent), 100 parts of composite fiber, and 4550 parts of water in parts by weight and pour them into the interior of the mixing device. Control the stirring speed of the mixing device to 100 rpm. When it is stirred into a viscous state, take 1000 parts of recycled aggregate and pour it therein. Continue stirring at the same speed for 40 minutes to obtain concrete.

[0079] The concrete prepared in Examples 2 to 4 was made into test pieces of 150 mm × 150 mm × 150 mm. After curing for 28 days, the mechanical properties of the test pieces were tested according to GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". The results are shown in Table 1 below:

[0080] Table 1

[0081] Compressive strength (MPa) Flexural strength (MPa) Example 2 49.2 5.8 Example 3 52.5 6.4 Example 4 48.2 5.7

[0082] As can be seen from Table 1, the raw material selection, proportioning and processing time control of the treating agent of the present invention play an important role in improving the strength of recycled concrete.

[0083] The above detailed description of the analytical methods involved in the present invention provides a detailed introduction. It should be noted that the above description is intended solely to help those skilled in the art better understand the methods and concepts of the present invention, and is not intended to limit the relevant content. Without departing from the principles of the present invention, those skilled in the art may make appropriate adjustments or modifications to the present invention, and such adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste, characterized in that: The specific steps are as follows: Step 1: Collect the solid waste generated by construction, sort out the debris inside the construction solid waste through magnetic separation and debris sorting, and crush the remaining construction solid waste such as cement blocks, bricks, and stones through multi-stage crushing, breaking them into 10-30mm blocks. Then, the crushed blocks are cleaned and transported to the corresponding location after cleaning for future use; Step 2: Collect the light aggregate waste, classify it after collection, crush the classified light aggregate waste into blocks, screen it with a screening device after crushing to obtain aggregates of different particle sizes, clean the crushed and screened aggregates, and transport them to the corresponding location for standby use after cleaning; Step 3: Mix the prepared construction solid waste block material and lightweight aggregate waste block material with each other, pour the mixture into the interior of the negative pressure bin, close the inlet and outlet channels of the negative pressure bin, set an air pump inside the negative pressure bin, extract the air inside the negative pressure bin by the air pump, so that a negative pressure is formed inside the negative pressure bin, and the negative pressure value in the negative pressure bin is controlled between -5KPa and -85KPa. During the negative pressure process, the mixture inside the negative pressure bin is continuously tumbled and stirred, the tumbling and stirring speed is controlled at 30-40 revolutions per minute, the pressure holding time is controlled at 20-30 minutes, and the internal mixture is heated in combination with infrared heat radiation during the pressure holding process. The heating temperature is controlled at 200-300 degrees Celsius and the heating time is 30-40 minutes to obtain recycled aggregate; Step 4: Pour 250-300 parts of mineral admixture, 325-335 parts of cement, 12-14 parts of antifreeze-type water-reducing agent, 10-12 parts of regulator, 6-8 parts of rust inhibitor, 12-14 parts of expansion agent, 80-100 parts of composite fiber and 450-550 parts of water into the mixing device according to the weight ratio. Control the stirring speed of the mixing device to 80-100 rpm. When it becomes viscous, take 800-1000 parts of recycled aggregate and pour it into it. Continue stirring at the same speed for 30-40 minutes to obtain concrete; The antifreeze type water reducing agent is prepared by the following steps: S1. Add terephthalic acid, triethylamine and NaOH aqueous solution to a dry three-necked flask equipped with a stirring device, a condensing reflux device and a nitrogen conduit, and introduce nitrogen for 10 minutes. Then, add 3-aminopropylene ethanol solution and DIC. After the addition is complete, stir and react for 3 hours at room temperature under N2 protection. After the reaction is completed, extract with chloroform three times, take the organic layer, dry it over anhydrous magnesium sulfate, filter, and finally rotary evaporate to obtain an intermediate product; The ratio of terephthalic acid, triethylamine, 3-aminopropylene and DIC is 0.05 mol:5.1 g:0.05 mol:6.3 g; The concentration of 3-aminopropylene dissolved in ethanol is 2.85 g / 30 mL; S2. Add the intermediate product and hydroxy silicone oil to a three-necked flask, stir and heat, control the temperature in the three-necked flask between 160-180° C., collect the by-product water through a condenser, stop heating when the water output reaches the theoretical amount and no water is output for 10 minutes, cool to room temperature, and obtain a modifier; The relative molecular mass of the hydroxy silicone oil is 500; the molar ratio of the intermediate product to the hydroxy silicone oil is 1:1; S3. Mix hydroxyethyl acrylate and the modifier evenly, transfer 2 / 3 to a four-necked flask, start stirring, transfer 2-methylprop-2-enyl polyethylene glycol ether to the flask, then add sodium methacrylate sulfonate, and transfer the remaining 1 / 3 of the mixture to a four-necked flask. Adjust the temperature to 28-32°C, keep the temperature constant for 10 minutes, then slowly add the sodium formaldehyde sulfoxylate solution to the four-necked flask, and simultaneously add an aqueous solution of acrylic acid and an aqueous solution of tert-butyl hydroperoxide. After the addition is complete, keep the mixture warm for 90 minutes, and neutralize with liquid alkali to a pH value of 5-7 to obtain a water reducer. The relative molecular mass of 2-methylprop-2-enyl polyethylene glycol ether is 2400; the molar ratio of acrylic acid to 2-methylprop-2-enyl polyethylene glycol ether is 7.5:1; the amounts of tert-butyl hydroperoxide, sodium formaldehyde sulfoxylate, sodium methacrylate sulfonate, modifier, and hydroxyethyl acrylate are 0.6%, 0.2%, 1.6%, 0.4%, and 0.1% of the mass of 2-methylprop-2-enyl polyethylene glycol ether, respectively.

2. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: In the step 1, the magnetic separation is to pick out the metal objects in the construction solid waste, and the debris sorting is to pick out the lighter or smaller impurities in the construction solid waste; the multi-stage crushing includes primary crushing, secondary crushing, and tertiary crushing, the primary crushing is a jaw crusher, the secondary crushing is a cone crusher, and the tertiary crushing is an impact crusher; the cleaning treatment is to wash the lumps to wash away the large amount of dust mixed inside them.

3. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: The mineral admixtures include fly ash, mineral powder and silicon powder, and the mass ratio of the three is 1:2:

1.

4. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: The conditioning agent is a mixture of soda ash and borax.

5. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: The cement is one of ordinary Portland cement, aluminate cement, composite Portland cement, sulfate-resistant Portland cement and fast-hardening Portland cement.

6. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: The composite fiber is one of steel fiber, polyacrylonitrile fiber and glass fiber.

7. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: Calculated by weight, the specific raw material components of the recycled concrete include: 250 parts of mineral admixture, 325 parts of cement, 12 parts of antifreeze-type water reducer, 10 parts of regulator, 6 parts of rust inhibitor, 12 parts of expansion agent, 80 parts of composite fiber, 450 parts of water and 800 parts of recycled aggregate.

8. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: Calculated by weight, the specific raw material components of the recycled concrete include: 275 parts of mineral admixture, 330 parts of cement, 13 parts of antifreeze-type water reducer, 11 parts of regulator, 7 parts of rust inhibitor, 13 parts of expansion agent, 90 parts of composite fiber, 500 parts of water and 900 parts of recycled aggregate.

9. The method for producing recycled concrete using construction solid waste and unburned lightweight aggregate waste according to claim 1, characterized in that: Calculated by weight, the specific raw material components of the recycled concrete include: 300 parts of mineral admixture, 335 parts of cement, 14 parts of antifreeze-type water reducer, 12 parts of regulator, 8 parts of rust inhibitor, 14 parts of expansion agent, 100 parts of composite fiber, 550 parts of water and 1000 parts of recycled aggregate.

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