Semi-rigid base material containing construction waste and method for preparing the same

Abstract

The application relates to the technical field of building materials, and discloses a semi-rigid base material containing construction waste and a preparation method thereof, which is prepared from the following raw materials in parts by weight: construction waste recycled aggregate 60-80 parts, basalt 20-30 parts, slag 10-20 parts, cementing material 10-20 parts, additive 5-15 parts and water 10-20 parts. The preparation method comprises the following steps: S1, crushing the basalt and the slag; S2, mixing and stirring the construction waste recycled aggregate, the basalt and the slag, adding the cementing material, the additive and the water, and uniformly stirring; S3, uniformly spreading the mixture in a preset mold or a construction road section, rolling with a vibrating road roller, covering a plastic film for moisturizing immediately after molding, and curing for 7 days. The whole realizes solid waste resource utilization, reduces the dependence on natural resources, and through material design and process optimization, the base material has good mechanical properties and environmental benefits, and is suitable for various road engineering scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a semi-rigid base material containing construction waste and a preparation method thereof. BACKGROUND

[0002] With the acceleration of urbanization, the construction industry is booming, at the same time, the amount of construction waste is also increasing day by day. A large amount of construction waste not only occupies valuable land resources, but also causes serious pollution to the environment. How to effectively handle and utilize construction waste has become a problem to be solved.

[0003] In road engineering, semi-rigid base material is one of the commonly used pavement structure layer materials. The traditional semi-rigid base material mainly uses natural sandstone and the like as aggregate, however, with the increasing scarcity of natural resources, its mining cost is increasing, and excessive mining has caused great damage to the ecological environment. Therefore, it is of great significance to find a material that can replace natural aggregate for reducing road construction cost and protecting the ecological environment.

[0004] In recent years, the research on applying construction waste as aggregate in semi-rigid base material has gradually increased. However, the current research still has some problems, for example, the composition of construction waste is complex, containing a large amount of impurities, which leads to unstable quality of recycled aggregate; the existing preparation method cannot fully exert the performance advantages of construction waste, and the strength, durability and other performances of the prepared semi-rigid base material are difficult to meet the actual engineering requirements. SUMMARY

[0005] (I) Technical problems solved

[0006] In view of the deficiencies of the prior art, the present application provides a semi-rigid base material containing construction waste and a preparation method thereof.

[0007] (II) Technical solutions

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions: a semi-rigid base material containing construction waste, which is composed of the following raw materials in parts by weight:

[0009] 60-80 parts of construction waste recycled aggregate, 20-30 parts of basalt, 10-20 parts of slag, 10-20 parts of cementitious material, 5-15 parts of additive, and 10-20 parts of water;

[0010] The construction waste recycled aggregate is treated by a coating process with a coating layer material;

[0011] The coating process comprises the following steps:

[0012] The construction waste recycled aggregate is placed in a drum coating device, and rotated at a speed of 50-80 r / min, and the coating layer material is uniformly sprayed on the surface of the aggregate by a spraying device. Under the action of the drum, the mixed liquid forms a uniform coating layer on the surface of the aggregate. During the spraying process, the spraying pressure is controlled at 0.2-0.3 MPa. The coated aggregate is placed in a well-ventilated environment and cured at room temperature for 2-3 h to form a stable coating structure.

[0013] Further, the construction waste is red brick, concrete block and masonry, and the mass ratio is 2-4:3-5:1-3.

[0014] Further, the preparation method of the construction waste recycled aggregate comprises the following steps:

[0015] A1, crushing

[0016] Primary crushing: the dried construction waste is sent into a jaw crusher for primary crushing, and the large construction waste is crushed to particles with a particle size of less than 100 mm;

[0017] Secondary crushing: the material after primary crushing is sent into an impact crusher for secondary crushing, and the particle size of the crushed material is controlled to be between 20-50 mm;

[0018] Tertiary crushing: the material after secondary crushing is sent into a cone crusher for tertiary crushing, and the particle size is crushed to be less than 20 mm;

[0019] A2, screening

[0020] Classification screening: the crushed material is sent into a vibrating screen for classification screening, and is set to 4.75 mm, 10 mm, 20 mm and 31.5 mm;

[0021] Grading adjustment: the mass ratio of coarse aggregate with a particle size of 4.75-31.5 mm to fine aggregate with a particle size of less than 4.75 mm is adjusted to 3-5:2-4;

[0022] A3, strengthening treatment

[0023] Chemical strengthening: the aggregate is soaked in a sodium silicate solution with a concentration of 5-10% for 24 h, and then taken out and dried.

[0024] Further, the preparation method of the coating layer material comprises the following steps:

[0025] B1, 100-120 parts of nano-titanium dioxide is added into deionized water to prepare a suspension with a mass fraction of 5%, the pH is adjusted to 2-3 with dilute nitric acid, and ultrasonic dispersion is performed at 40-60 kHz for 10-20 min. The reaction mixture is transferred to a three-necked flask, nitrogen is introduced for protection, the temperature is raised to 70-80 DEG C, 10-15 parts of hydroxyethyl acrylate and 0.2-0.45 parts of benzoyl peroxide are added in sequence, and stirring is performed at a rotation speed of 400-500 r / min for 3-4 h. After the reaction is completed, centrifugal separation is performed at 8000 r / min for 10-15 min, washing is performed with deionized water and ethanol alternately for 3 times, and vacuum drying is performed at 60-80 DEG C for 4-6 h to obtain nano-titanium dioxide graft 1;

[0026] B2, nano-titanium dioxide graft 1 is taken and added into N,N-dimethylformamide to prepare a suspension with a mass fraction of 8%, ultrasonic dispersion is performed at 50-60 kHz for 10-15 min, the reaction mixture is transferred to a four-necked flask, nitrogen is introduced for protection, the temperature is raised to 60-70 DEG C, 8-12 parts of maleic anhydride and 0.08-0.24 parts of triethylamine are added, and stirring is performed at a rotation speed of 500-600 r / min for 2-3 h. After the reaction is completed, the reaction solution is poured into excess ethanol for precipitation, standing is performed for 30-60 min, centrifugal separation is performed at 10000 r / min for 5-10 min, the precipitate is washed with ethanol for 3-4 times, and vacuum drying is performed at 60-80 DEG C for 6-8 h to obtain nano-titanium dioxide graft 2;

[0027] B3, nano-titanium dioxide graft 2 is taken and added into deionized water to prepare a suspension with a mass fraction of 10%, the pH is adjusted to 4-5 with dilute hydrochloric acid, and ultrasonic dispersion is performed at 50-60 kHz for 10-20 min. The reaction mixture is transferred to a three-necked flask, stirring is performed at a rotation speed of 400-500 r / min at room temperature, 0.15-0.4 parts of condensing agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is added, stirring is performed for 10-15 min, 5-8 parts of amino silicone oil is slowly added dropwise, the temperature is raised to 40-50 DEG C after the dropwise addition is completed, and stirring is continuously performed for 4-5 h. After the reaction is completed, centrifugal separation is performed at 12000 r / min for 5-10 min, the precipitate is washed with deionized water until the supernatant is neutral, and vacuum drying is performed at 60-80 DEG C for 10-12 h to obtain nano-titanium dioxide graft 3;

[0028] B4, the nano titanium dioxide graft 3 is added into 200 parts of deionized water, 1~5 parts of mass fraction 0.5% polyethylene glycol 400 is added as dispersing agent, 40~50 kHz ultrasonic dispersion is carried out for 20~40 min, and modified nano titanium dioxide dispersion is obtained;500~800 parts of water-based polyurethane are added in the stirred tank, low-speed stirring is carried out at a rotating speed of 150~200 r / min, the modified nano titanium dioxide dispersion is slowly added, continuous stirring is carried out for 10~20 min, the rotating speed is increased to 250~300 r / min, 15~40 parts of antifreeze agent is added, stirring is carried out for 10~30 min, finally 15~30 parts of crosslinking agent is added, and the rotating speed is kept for stirring for 25~30 min, to obtain a coating material.

[0029] Further, the antifreeze agent is one of ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate and ethylene glycol butyl ether acetate.

[0030] Further, the crosslinking agent is one of toluene diisocyanate, diphenyl methane diisocyanate and p-phenylene diisocyanate.

[0031] Further, the cementing material is one of cement, lime and fly ash.

[0032] Further, the additive is a reinforcing agent and a stabilizer, the reinforcing agent is one of silica fume, metakaolin and calcium acrylate, and the stabilizer is one of sodium sulfate, sodium carbonate and calcium chloride.

[0033] Further, the preparation method of the semi-rigid base material containing construction waste comprises the following steps:

[0034] S1, basalt is crushed and sieved to a particle size of 5~20 mm, surface dust is removed by water washing method, and drying is carried out until the water content is ≤2%;

[0035] Granulated blast furnace slag is selected, ball mill grinding is carried out to a specific surface area of 350~450 m 2 / kg, then drying is carried out in a 105℃ oven for 2 h, and after cooling, it is ready for use;

[0036] S2, the treated construction waste recycled aggregate, basalt and slag are poured into a forced mixer, dry mixing is carried out for 1~2 min, cementing material and additive are added, dry mixing is continued for 2~3 min, water is added according to the proportion, and stirring is carried out for 3~5 min while adding water;

[0037] S3, evenly spread the mixture in the preset mold or construction road section, use the vibrating roller to roll, first static pressure 1 time, then vibration compaction 3 times, cover the plastic film to keep moist after forming, stand still at room temperature for 24 hours, after removing the film, sprinkle water on the test piece or road section to keep the surface wet, cover the burlap or geotextile, sprinkle water 3 times a day to keep wet, the curing temperature is controlled at 20±2 DEG C, the relative humidity is greater than or equal to 95%, the curing time is 7 days, then natural curing for 21 days, during which vehicles are prohibited from rolling or heavy objects are prohibited from being placed.

[0038] (Three) beneficial technical effects

[0039] The application realizes multiple advantages through the synergistic effect of multiple components: taking the construction waste recycled aggregate as the core, the composite matrix is formed by matching basalt and slag, which not only absorbs solid waste but also utilizes the high strength of basalt and the activity of slag to improve the overall structural stability; the recycled aggregate treated by the coating process enhances the interfacial bonding with the cementitious material through nano titanium dioxide grafting modification, and reduces the adverse effects of aggregate water absorption on performance; the cementitious material and the additive synergistically stimulate the activity of each component, promote the hydration reaction to generate stable cementitious products, and improve the material strength and durability.

[0040] In the preparation process of the semi-rigid base material, the graded crushing and screening ensures that the aggregate grade is reasonable, the chemical strengthening and coating process improve the performance defects of the recycled aggregate, and the multi-stage curing ensures the steady development of the strength. The whole realizes the resource utilization of solid waste, reduces the dependence on natural resources, and at the same time, through material design and process optimization, the base material has good mechanical properties and environmental benefits, and is suitable for various road engineering scenes. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0042] The components of the semi-rigid base material of the application are all commercially available unless otherwise specified.

[0043] The parts used in the application are all parts by weight;

[0044] Embodiment 1

[0045] The semi-rigid base material containing construction waste is composed of the following raw materials by weight:

[0046] The construction waste recycled aggregate is 60 parts, the basalt is 20 parts, the slag is 10 parts, the cementitious material is 10 parts, the additive is 5 parts, and the water is 10 parts.

[0047] The construction waste is red brick, concrete block and masonry, and the mass ratio is 2:3:1.

[0048] The cementitious material is cement.

[0049] The additive is a reinforcing agent and a stabilizer, the reinforcing agent is silica fume, and the stabilizer is sodium sulfate.

[0050] The construction waste recycled aggregate is processed by a coating process with a coating layer material;

[0051] The coating process comprises the following steps:

[0052] The construction waste recycled aggregate is placed in a rotary drum coating device, and rotates at a speed of 50 r / min. The coating layer material is uniformly sprayed on the surface of the aggregate by a spraying device. Under the action of the rotary drum, the mixed liquid forms a uniform coating layer on the surface of the aggregate. During the spraying process, the spraying pressure is controlled at 0.2 MPa. The coated aggregate is placed in a well-ventilated environment and cured at room temperature for 2 h to form a stable coating structure.

[0053] The preparation method of the construction waste recycled aggregate comprises the following steps:

[0054] A1, crushing

[0055] Primary crushing: the dried construction waste is fed into a jaw crusher for primary crushing, and the large construction waste is crushed to particles with a particle size of less than 100 mm;

[0056] Secondary crushing: the material after primary crushing is fed into an impact crusher for secondary crushing, and the particle size of the crushed material is controlled to be between 20-50 mm;

[0057] Tertiary crushing: the material after secondary crushing is fed into a cone crusher for tertiary crushing, and the particle size is crushed to less than 20 mm;

[0058] A2, screening

[0059] Classification screening: the crushed material is fed into a vibrating screen for classification screening, and is set to 4.75 mm, 10 mm, 20 mm and 31.5 mm;

[0060] Grading adjustment: the mass ratio of coarse aggregate with a particle size of 4.75-31.5 mm to fine aggregate with a particle size of less than 4.75 mm is adjusted to 3:2;

[0061] A3, strengthening treatment

[0062] Chemical strengthening: the aggregate is soaked in a 5% sodium silicate solution for 24 h, and then taken out and dried.

[0063] The preparation method of the coating layer material comprises the following steps:

[0064] B1, 100 parts of nanometer titanium dioxide was added to deionized water to prepare a suspension with a mass fraction of 5%, and the pH was adjusted to 2 with dilute nitric acid, and then ultrasonic dispersion was performed at 40 kHz for 10 min. The mixture was transferred to a three-necked flask, and then nitrogen was introduced for protection. The temperature was raised to 70 DEG C, and then 10 parts of hydroxyethyl acrylate and 0.2 parts of benzoyl peroxide were added in sequence. The stirring speed was 400 r / min, and the reaction was carried out for 3 h. After the reaction was completed, centrifugal separation was performed at 8000 r / min for 10 min. The precipitate was washed with deionized water and ethanol alternately for 3 times, and then vacuum drying was performed at 60 DEG C for 4 h to obtain nanometer titanium dioxide graft 1;

[0065] B2, nanometer titanium dioxide graft 1 was taken and added to N,N-dimethylformamide to prepare a suspension with a mass fraction of 8%. Ultrasonic dispersion was performed at 50 kHz for 10 min. The mixture was transferred to a four-necked flask, and then nitrogen was introduced for protection. The temperature was raised to 60 DEG C, and then 8 parts of maleic anhydride and 0.08 parts of triethylamine were added. The stirring speed was 500 r / min, and the reaction was carried out for 2 h. After the reaction was completed, the reaction solution was poured into excess ethanol for precipitation. The mixture was allowed to stand for 30 min, and then centrifugal separation was performed at 10000 r / min for 5 min. The precipitate was washed with ethanol for 3 times, and then vacuum drying was performed at 60 DEG C for 6 h to obtain nanometer titanium dioxide graft 2;

[0066] B3, nanometer titanium dioxide graft 2 was taken and added to deionized water to prepare a suspension with a mass fraction of 10%. The pH was adjusted to 4 with dilute hydrochloric acid, and then ultrasonic dispersion was performed at 50 kHz for 10 min. The mixture was transferred to a three-necked flask, and then stirring was performed at room temperature at a stirring speed of 400 r / min. 0.15 parts of condensing agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride was added, and then stirring was performed for 10 min. 5 parts of amino silicon oil was added dropwise. After the dropwise addition was completed, the temperature was raised to 40 DEG C, and then stirring was continued for 4 h. After the reaction was completed, centrifugal separation was performed at 12000 r / min for 5 min. The precipitate was washed with deionized water until the supernatant was neutral. Vacuum drying was performed at 60 DEG C for 10 h to obtain nanometer titanium dioxide graft 3;

[0067] B4, nanometer titanium dioxide graft 3 was added to 200 parts of deionized water, and 1 part of polyethylene glycol 400 with a mass fraction of 0.5% was added as a dispersing aid. Ultrasonic dispersion was performed at 40 kHz for 20 min to obtain a modified nanometer titanium dioxide dispersion. In a stirring kettle, 500 parts of water-based polyurethane was added, and then stirring was performed at a low speed of 150 r / min. The modified nanometer titanium dioxide dispersion was added slowly, and then stirring was continued for 10 min. The stirring speed was raised to 250 r / min, and then 15 parts of antifreeze was added. Stirring was performed for 10 min. Finally, 15 parts of crosslinking agent was added, and then stirring was performed at the same speed for 25 min to obtain a coating material.

[0068] The antifreeze is ethylene glycol methyl ether acetate.

[0069] The cross-linking agent is toluene diisocyanate.

[0070] The preparation method of the semi-rigid base material containing construction waste comprises the following steps:

[0071] S1, crushing and screening basalt to a particle size of 5-20 mm, removing surface dust by water washing method, and drying to a water content of ≤2%;

[0072] Select granulated blast furnace slag, grind to a specific surface area of 350-450 m 2 / kg by a ball mill, then dry in an oven at 105℃ for 2h, and cool to prepare for use;

[0073] S2, pour the treated construction waste recycled aggregate, basalt, and slag into a forced mixer, dry mix for 1min, add cementitious material and additives, continue to dry mix for 2min, add water in proportion, and stir for 3min while adding water;

[0074] S3, evenly spread the mixture in a preset mold or construction road section, roll with a vibrating road roller, first static pressure for 1 pass, then vibration rolling for 3 passes, immediately cover plastic film after molding to keep moist, stand at room temperature for 24h, after removing the film, sprinkle water on the test piece or road section to make the surface wet, cover burlap or geotextile, sprinkle water 3 times a day to keep it wet, the curing temperature is controlled at 20±2℃, the relative humidity is ≥95%, the curing time is 7 days, then change to natural curing for 21 days, during which vehicles are prohibited from rolling or heavy objects are prohibited from stacking.

[0075] Example 2

[0076] The semi-rigid base material containing construction waste is composed of the following weight parts of raw materials:

[0077] Construction waste recycled aggregate 70 parts, basalt 25 parts, slag 15 parts, cementitious material 15 parts, additives 10 parts, and water 15 parts;

[0078] The construction waste is red brick, concrete block, and masonry, with a mass ratio of 3:4:2.

[0079] The cementitious material is lime.

[0080] The additives are reinforcing agents and stabilizers, the reinforcing agent is metakaolin, and the stabilizer is sodium carbonate.

[0081] The construction waste recycled aggregate is treated by a coating process with a coating layer material;

[0082] The coating process comprises the following steps:

[0083] The construction waste recycled aggregate is placed in a drum coating device, rotates at a speed of 60 r / min, and the coating layer material is uniformly sprayed on the surface of the aggregate by a spraying device. Under the action of the drum, the mixed liquid forms a uniform coating layer on the surface of the aggregate. During the spraying process, the spraying pressure is controlled at 0.2 MPa. The coated aggregate is placed in a well-ventilated environment and cured at room temperature for 2.5 h to form a stable coating structure.

[0084] The preparation method of the construction waste recycled aggregate comprises the following steps:

[0085] A1, crushing

[0086] Primary crushing: the construction waste after airing is sent into a jaw crusher for primary crushing, and the large construction waste is crushed to particles with a particle size of less than 100 mm;

[0087] Secondary crushing: the material after the primary crushing is sent into a counterattack crusher for secondary crushing, and the particle size of the crushed material is controlled to be between 20-50 mm;

[0088] Tertiary crushing: the material after the secondary crushing is sent into a cone crusher for tertiary crushing, and the particle size is crushed to be less than 20 mm;

[0089] A2, screening

[0090] Classification screening: the crushed material is sent into a vibrating screen for classification screening, and is set to 4.75 mm, 10 mm, 20 mm and 31.5 mm;

[0091] Grading adjustment: the mass ratio of the coarse aggregate with a particle size of 4.75-31.5 mm to the fine aggregate with a particle size of less than 4.75 mm is 4:3;

[0092] A3, strengthening treatment

[0093] Chemical strengthening: the aggregate is soaked in a sodium silicate solution with a concentration of 8% for 24 h, and then taken out and dried.

[0094] The preparation method of the coating layer material comprises the following steps:

[0095] B1, 110 parts of nano titanium dioxide are added to deionized water to prepare a suspension with a mass fraction of 5%, the pH is adjusted to 2 with dilute nitric acid, ultrasonic dispersion is performed for 15 min at 50 kHz, the mixture is transferred to a three-necked flask, nitrogen is introduced for protection, the temperature is raised to 75℃, 12 parts of hydroxyethyl acrylate and 0.3 parts of benzoyl peroxide are added in turn, stirring is performed at a speed of 450 r / min for 3.5 h, after the reaction is completed, centrifugal separation is performed at 8000 r / min for 12 min, washing is performed with deionized water and ethanol alternately for 3 times, and vacuum drying is performed at 70℃ for 5 h to obtain a nano titanium dioxide graft 1;

[0096] B2, take nano titanium dioxide graft 1, add to N, N-dimethylformamide, prepare into a mass fraction of 8% suspension, 55 kHz ultrasonic dispersion for 15 min, transfer to a four-necked flask, protect by purging with nitrogen, warm up to 65 DEG C, add 10 parts of maleic anhydride and 0.1 parts of triethylamine, stir at 550 r / min for 2.5 h, after the reaction, pour the reaction liquid into excess ethanol to precipitate, stand for 40 min, centrifugal separation at 10000 r / min for 10 min, wash the precipitate with ethanol 4 times, vacuum dry at 70 DEG C for 7h, obtain nano titanium dioxide graft 2;

[0097] B3, take nano titanium dioxide graft 2, add to deionized water, prepare into a mass fraction of 10% suspension, adjust pH to 5 with dilute hydrochloric acid, 55 kHz ultrasonic dispersion for 15 min, transfer to a three-necked flask, stir at room temperature at 450 r / min, add 0.3 parts of condensing agent 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride, stir for 15 min, slowly drop 6 parts of amino silicone oil, after drop completion, warm up to 45 DEG C, continue to stir for 4.5 h, after the reaction, centrifugal separation at 12000 r / min for 10 min, wash the precipitate with deionized water until the supernatant is neutral, vacuum dry at 70 DEG C for 10 h, obtain nano titanium dioxide graft 3;

[0098] B4, add nano titanium dioxide graft 3 to 200 parts of deionized water, at the same time, add 3 parts of mass fraction of 0.5% polyethylene glycol 400 as dispersing agent, 45 kHz ultrasonic dispersion for 30 min, obtain modified nano titanium dioxide dispersion; in a stirred tank, add 600 parts of water-based polyurethane, stir at low speed at 180 r / min, slowly add the modified nano titanium dioxide dispersion, continue to stir for 15 min, increase the stirring speed to 280 r / min, add 25 parts of antifreeze, stir for 20 min, finally add 20 parts of crosslinking agent, keep the stirring speed and stir for 25 min, obtain coating material.

[0099] The antifreeze is ethylene glycol ethyl ether acetate.

[0100] The crosslinking agent is diphenyl methane diisocyanate.

[0101] The preparation method of the semi-rigid base material containing construction waste comprises the following steps:

[0102] S1, crush basalt to a particle size of 5-20 mm, remove surface dust by water washing method, and dry to a water content of less than or equal to 2%;

[0103] Select granulated blast furnace slag, grind to a specific surface area of 350-450 m 2 / kg, then dried in an oven at 105℃ for 2 h, and after cooling, stored for later use;

[0104] S2, pour the treated construction waste recycled aggregate, basalt, and slag into a forced mixer, dry mix for 2 min, add cementitious material and additives, continue to dry mix for 2 min, add water in proportion, and stir for 4 min while adding water;

[0105] S3, evenly spread the mixture in the preset mold or construction section, use a vibrating roller to compact, first static pressure 1 pass, then vibration compaction 3 passes, immediately cover plastic film after molding to keep moist, stand at room temperature for 24 h, after removing the film, sprinkle water on the test piece or road section to make the surface wet, cover burlap or geotextile, sprinkle water 3 times a day to keep it wet, the curing temperature is controlled at 20±2℃, the relative humidity is ≥95%, the curing time is 7 days, then natural curing for 21 days, during which vehicles are prohibited from rolling or heavy objects are prohibited from being placed.

[0106] Example 3

[0107] The semi-rigid base material containing construction waste is composed of the following raw materials by weight:

[0108] Construction waste recycled aggregate 80 parts, basalt 30 parts, slag 20 parts, cementitious material 20 parts, additives 15 parts, water 20 parts;

[0109] The construction waste is red brick, concrete block, and masonry, with a mass ratio of 4:5:3.

[0110] The cementitious material is fly ash.

[0111] The additives are reinforcing agents and stabilizers, the reinforcing agent is calcium acrylate, and the stabilizer is calcium chloride.

[0112] The construction waste recycled aggregate is treated by a coating process with a coating layer material;

[0113] The coating process includes the following steps:

[0114] Place the construction waste recycled aggregate in a rotary drum coating device and rotate at a speed of 80 r / min, uniformly spray the coating layer material on the surface of the aggregate through the spray device, under the action of the rotary drum, the mixed liquid forms a uniform coating layer on the surface of the aggregate, control the spray pressure to be 0.3 MPa during the spraying process, place the coated aggregate in a well-ventilated environment, and solidify at room temperature for 3 h to form a stable coating structure.

[0115] The preparation method of the construction waste recycled aggregate includes the following steps:

[0116] A1, crushing

[0117] Primary crushing: the dried construction waste is sent into a jaw crusher for primary crushing, and the large construction waste is crushed to particles with a particle size of less than 100 mm;

[0118] Secondary crushing: the material after the primary crushing is sent into a counterattack crusher for secondary crushing, and the particle size of the material after the crushing is controlled to be between 20-50 mm;

[0119] Tertiary crushing: the material after the secondary crushing is sent into a cone crusher for tertiary crushing, and the particle size is less than 20 mm;

[0120] A2, screening

[0121] Classification screening: the crushed material is sent into a vibrating screen for classification screening, and is set to 4.75 mm, 10 mm, 20 mm, and 31.5 mm;

[0122] Grading adjustment: the mass ratio of the coarse aggregate with a particle size of 4.75-31.5 mm to the fine aggregate with a particle size of less than 4.75 mm is 5:4;

[0123] A3, strengthening treatment

[0124] Chemical strengthening: the aggregate is soaked in a 10% sodium silicate solution for 24 h, and then taken out and dried.

[0125] The preparation method of the coating layer material comprises the following steps:

[0126] B1, 120 parts of nano-titanium dioxide are added to deionized water to prepare a suspension with a mass fraction of 5%, the pH is adjusted to 3 with dilute nitric acid, and ultrasonic dispersion is performed at 60 kHz for 20 min. The reaction solution is transferred to a three-necked flask, nitrogen is introduced for protection, the temperature is raised to 80°C, 15 parts of hydroxyethyl acrylate and 0.45 parts of benzoyl peroxide are sequentially added, and stirring is performed at a speed of 500 r / min for 4 h. After the reaction is completed, centrifugal separation is performed at 8000 r / min for 15 min, washing is performed with deionized water and ethanol alternately for 3 times, and vacuum drying is performed at 80°C for 6 h to obtain a nano-titanium dioxide graft 1;

[0127] B2, the nano-titanium dioxide graft 1 is taken and added to N,N-dimethylformamide to prepare a suspension with a mass fraction of 8%, ultrasonic dispersion is performed at 60 kHz for 15 min, the reaction solution is transferred to a four-necked flask, nitrogen is introduced for protection, the temperature is raised to 70°C, 12 parts of maleic anhydride and 0.24 parts of triethylamine are added, and stirring is performed at a speed of 600 r / min for 3 h. After the reaction is completed, the reaction solution is poured into an excess of ethanol for precipitation, and standing is performed for 60 min. Centrifugal separation is performed at 10000 r / min for 10 min, the precipitate is washed with ethanol for 4 times, and vacuum drying is performed at 80°C for 8 h to obtain a nano-titanium dioxide graft 2;

[0128] B3, take nano titanium dioxide graft 2, add to deionized water, prepare into 10% mass fraction suspension, adjust pH to 5 with dilute hydrochloric acid, 60 kHz ultrasonic dispersion for 20 min, transfer to three-necked flask, stirring at room temperature at 500 r / min, add 0.4 parts of condensing agent 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride, stir for 15 min, slowly drop 8 parts of amino silicone oil, after drop completion, warm to 50 DEG C, continue to stir for 5 h, after reaction, centrifugal separation at 12000 r / min for 10 min, wash the precipitate with deionized water until the supernatant is neutral, vacuum drying at 80 DEG C for 12 h, obtain nano titanium dioxide graft 3;

[0129] B4, add nano titanium dioxide graft 3 to 200 parts of deionized water, add 5 parts of 0.5% mass fraction polyethylene glycol 400 as dispersing agent, 50 kHz ultrasonic dispersion for 40 min, obtain modified nano titanium dioxide dispersion; in a stirred tank, add 800 parts of water-based polyurethane, low speed stirring at 200 r / min, slowly add modified nano titanium dioxide dispersion, continue to stir for 20 min, increase the stirring speed to 300 r / min, add 40 parts of antifreeze, stir for 30 min, finally add 30 parts of crosslinking agent, keep stirring at the same speed for 30 min, obtain coating material.

[0130] The antifreeze is ethylene glycol butyl ether acetate.

[0131] The crosslinking agent is p-phenylene diisocyanate.

[0132] The preparation method of the semi-rigid base material containing construction waste comprises the following steps:

[0133] S1, crush basalt to a particle size of 5-20 mm, remove surface dust by water washing method, and dry to a water content of less than or equal to 2%;

[0134] Select granulated blast furnace slag, grind to a specific surface area of 350-450 m 2 / kg by a ball mill, then dry in a 105 DEG C oven for 2 h, and cool to be used;

[0135] S2, pour the treated construction waste recycled aggregate, basalt and slag into a forced mixer, dry mix for 2 min, add cementitious materials and additives, continue to dry mix for 3 min, add water according to the proportion, and stir for 5 min while adding water;

[0136] S3, uniformly spread the mixture in the preset mold or construction road section, use the vibrating roller to roll, first static pressure 1 time, then vibration rolling 3 times, cover the plastic film to keep moist after molding, stand for 24 h at room temperature, after removing the film, sprinkle water on the test piece or road section to keep the surface moist, cover the burlap or geotextile, sprinkle water 3 times a day to keep moist, the curing temperature is controlled at 20±2℃, the relative humidity is ≥95%, the curing time is 7 days, then natural curing for 21 days, during which vehicles are prohibited from rolling or heavy objects are prohibited from being placed.

[0137] Comparative Example 1: The construction waste recycled aggregate is not treated with a coating material, and the remaining materials and processes are the same as in Example 1.

[0138] Comparative Example 2: Basalt is not added, and the remaining materials and processes are the same as in Example 1.

[0139] Comparative Example 3: The construction waste recycled aggregate and basalt are replaced with natural crushed stone and river sand, and the remaining materials and processes are the same as in Example 1.

[0140] Performance Test:

[0141] 1. 7 d compressive strength: test standard JTG E51-2009, 150 mm cube test piece, press loading rate 1.5 kN / s, measure the failure load;

[0142] 2. 28 d compressive strength: test standard JTG E51-2009, same as 7 d test, test after standard curing for 28 d;

[0143] 3. Splitting strength: test standard JTG E51-2009, cylindrical test piece (φ150x150 mm), three-point bending loading, calculate the splitting strength;

[0144] 4. Compressive resilience modulus: test standard JTG E51-2009, graded loading to 400 kPa, measure the axial deformation, calculate the resilience modulus;

[0145] 5. Freeze-thaw cycle mass loss rate: test standard JTG E51-2009, -18℃ freezing for 4 h→20℃ thawing for 4 h as 1 cycle, measure the mass loss rate after 30 cycles;

[0146] 6. Water absorption rate: test standard GB / T 17431.1-2010, dry test piece immersed in water for 24 h, calculate the ratio of water absorption mass to dry mass.

[0147] Table 1 (unit: MPa)

[0148]

[0149] Table 2 (unit: %)

[0150]

[0151] From the above table, after the coating process of construction waste recycled aggregate and the addition of basalt, the interface bonding between the aggregate and the cementitious material is enhanced, which can effectively improve the compressive strength, splitting strength and resilient modulus of the semi-rigid base material, and the coating layer effectively seals the pores of the construction waste aggregate, reduces the water intrusion and significantly improves the water absorption.

[0152] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A semi-rigid base material containing construction waste, characterized by, Consist of the following weight parts raw materials: 60~80 parts of construction waste recycled aggregate, 20~30 parts of basalt, 10~20 parts of slag, 10~20 parts of cementitious material, 5~15 parts of additive, and 10~20 parts of water; The construction waste recycled aggregate is treated by a coating process with a coating layer material; The coating process comprises the following steps: The construction waste recycled aggregate is placed in a rotary drum coating device and rotated at a speed of 50~80 r / min, the coating layer material is uniformly sprayed on the surface of the aggregate by a spraying device, under the action of the rotary drum, the mixed liquid forms a uniform coating layer on the surface of the aggregate, during the spraying process, the spraying pressure is controlled at 0.2~0.3 MPa, the coated aggregate is placed in a well-ventilated environment and solidified at room temperature for 2~3 h to form a stable coating structure; The preparation method of the coating layer material comprises the following steps: B1, 100~120 parts of nano-titanium dioxide are added to deionized water to prepare a suspension with a mass fraction of 5%, the pH is adjusted to 2~3 with dilute nitric acid, ultrasonic dispersion is performed at 40~60 kHz for 10~20 min, it is transferred to a three-necked flask, nitrogen is introduced for protection, the temperature is raised to 70~80℃, 10~15 parts of hydroxyethyl acrylate and 0.2~0.45 parts of benzoyl peroxide are added in turn, stirring is performed at a speed of 400~500 r / min for 3~4 h, after the reaction is completed, centrifugal separation is performed at 8000 r / min for 10~15 min, washing is performed with deionized water and ethanol alternately for 3 times, vacuum drying is performed at 60~80℃ for 4~6 h to obtain nano-titanium dioxide graft 1; B2, take nano-titanium dioxide graft 1, add it to N,N-dimethylformamide to prepare a suspension with a mass fraction of 8%, ultrasonic dispersion is performed at 50~60 kHz for 10~15 min, it is transferred to a four-necked flask, nitrogen is introduced for protection, the temperature is raised to 60~70℃, 8~12 parts of maleic anhydride and 0.08~0.24 parts of triethylamine are added, stirring is performed at a speed of 500~600 r / min for 2~3 h, after the reaction is completed, the reaction liquid is poured into excess ethanol for precipitation, it is left to stand for 30~60 min, centrifugal separation is performed at 10000 r / min for 5~10 min, the precipitate is washed with ethanol for 3~4 times, vacuum drying is performed at 60~80℃ for 6~8 h to obtain nano-titanium dioxide graft 2; B3, take nano titanium dioxide graft 2, add to deionized water, prepare into 10% mass fraction suspension, adjust pH to 4~5 with dilute hydrochloric acid, 50~60 kHz ultrasonic dispersion for 10~20 min, transfer to three-necked flask, stir at room temperature at 400~500 r / min, add 0.15~0.4 parts of condensing agent 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride, stir for 10~15 min, slowly drop 5~8 parts of amino silicone oil, after drop completion, warm to 40~50 DEG C, continue to stir for 4~5 h, after reaction, centrifugal separation at 12000 r / min for 5~10 min, wash the precipitate with deionized water until the supernatant is neutral, vacuum dry at 60~80 DEG C for 10~12 h, obtain nano titanium dioxide graft 3; B4, add nano titanium dioxide graft 3 to 200 parts of deionized water, add 1~5 parts of 0.5% mass fraction polyethylene glycol 400 as dispersing agent, 40~50 kHz ultrasonic dispersion for 20~40 min, obtain modified nano titanium dioxide dispersion; in a stirred tank, add 500~800 parts of water-based polyurethane, stir at low speed at 150~200 r / min, slowly add the modified nano titanium dioxide dispersion, continue to stir for 10~20 min, increase the stirring speed to 250~300 r / min, add 15~40 parts of antifreeze agent, stir for 10~30 min, finally add 15~30 parts of crosslinking agent, keep stirring at the stirring speed for 25~30 min, obtain coating material.

2. The construction and demolition waste-containing semi-rigid base material according to claim 1, characterized by, The construction waste is red brick, concrete block and brickwork, and the mass ratio is 2~4:3~5:1~3.

3. The construction and demolition waste-containing semi-rigid base material according to claim 1, characterized by, The preparation method of the construction waste recycled aggregate comprises the following steps: A1, crushing Primary crushing: the construction waste after airing is sent into a jaw crusher for primary crushing, and the large construction waste is crushed into particles with a particle size of less than 100 mm; Secondary crushing: the material after the primary crushing is sent into an impact crusher for secondary crushing, and the particle size of the crushed material is controlled to be between 20~50 mm; Tertiary crushing: the material after the secondary crushing is sent into a cone crusher for tertiary crushing, and the particle size is less than 20 mm; A2, screening Classification screening: the crushed material is sent into a vibrating screen for classification screening, and the vibrating screen is set to 4.75 mm, 10 mm, 20 mm and 31.5 mm; Gradation adjustment: the mass ratio of the coarse aggregate with a particle size of 4.75~31.5 mm to the fine aggregate with a particle size of less than 4.75 mm is 3~5:2~4; A3, strengthening treatment Chemical strengthening: the aggregate is soaked in a sodium silicate solution with a concentration of 5~10% for 24 h, and then taken out and dried.

4. The construction and demolition waste-containing semi-rigid base material according to claim 1, characterized by, The antifreeze agent is one of ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate and ethylene glycol butyl ether acetate.

5. The construction and demolition waste-containing semi-rigid base material according to claim 1, characterized by, The crosslinking agent is one of toluene diisocyanate, diphenyl methane diisocyanate and p-phenylene diisocyanate.

6. The construction and demolition waste-containing semi-rigid base material according to claim 1, characterized by, The cementing material is one of cement, lime and fly ash.

7. The construction and demolition waste-containing semi-rigid base material according to claim 1, characterized by, The additive is a reinforcing agent and a stabilizer, the reinforcing agent is one of silica ash, metakaolin and calcium propionate, and the stabilizer is one of sodium sulfate, sodium carbonate and calcium chloride.

8. A method according to any one of claims 1 to 7, c h a r a c t e r i s e d i n that The method comprises the following steps: S1, crushing and screening basalt to a particle size of 5-20 mm, removing surface dust by water washing method, and drying to a water content of ≤2%; Granulated blast furnace slag was selected, ground by a ball mill to a specific surface area of 350~450 m 2 / kg, and then dried in an oven at 105°C for 2 h, and after cooling, reserved for use; S2, pouring the treated construction waste recycled aggregate, basalt and slag into a forced mixer, dry mixing for 1-2 min, adding cementing material and additive, continuing to dry mix for 2-3 min, adding water in proportion, and stirring for 3-5 min while adding water; S3, uniformly spreading the mixture in a preset mold or construction road section, rolling with a vibrating road roller, first static pressure for 1 pass, then vibrating rolling for 3 passes, immediately covering plastic film after molding to keep moist, standing at room temperature for 24 h, after removing the film, spraying water on the test piece or road section to keep the surface wet, covering burlap or geotextile, spraying water 3 times a day to keep wet, the curing temperature is controlled at 20±2℃, the relative humidity is ≥95%, the curing time is 7 days, then natural curing for 21 days, during which vehicles are prohibited from rolling or heavy objects from being stacked.

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