Preparation process of environment-friendly quartz stone powder-containing cement-based pavement patching material

Abstract

The invention relates to the technical field of building materials, and discloses a preparation process of an environment-friendly quartz stone powder-containing cement-based pavement patching material, which is prepared from the following raw materials in parts by weight: 167 to 180 parts of cement, 475 to 486 parts of machine-made sand, 50 to 60 parts of quartz stone powder, 8.35 to 9.62 parts of gypsum, 1 to 3 parts of water reducing agent, PVC (Polyvinyl Chloride) fiber with the addition amount not greater than 1 percent of the total volume, and 230 to 250 parts of water, the machine-made sand is prepared from waste quartz stone, the particle size of the quartz stone powder is 1-20 microns, the SiO2 content is greater than or equal to 99%, the cement is 42.5 type ordinary Portland cement, the initial setting time is longer than 3 hours, the final setting time is 6-10 hours, the 28-day breaking strength of the cement is greater than or equal to 6.5 MPa, and the compressive strength is greater than or equal to 42.5 MPa. The machine-made sand and the quartz stone powder are prepared from the waste quartz stone, so that resource utilization of building waste is realized, exploitation of natural river sand is reduced, and damage to the environment is reduced. Meanwhile, the quartz stone powder is used for partially replacing cement, so that energy consumption and carbon dioxide emission in the cement production process are reduced, and the environment-friendly concept of sustainable development is met.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly to a preparation process of an environmentally friendly quartz powder-containing cement-based pavement repair material. Background Art

[0002] With the booming development of the global cement industry, the application of cement concrete pavements is becoming increasingly widespread. However, during the long-term use of cement concrete pavements, due to reasons such as vehicle overloading, subgrade settlement, and insufficient maintenance, diseases such as cracks are likely to occur. These cracks not only affect the aesthetics and driving comfort of the road, but also cause rainwater to seep in, further damaging the pavement structure and affecting driving safety. Therefore, it is particularly important to develop an efficient and environmentally friendly pavement repair material.

[0003] Traditional pavement repair materials mainly rely on natural river sand as fine aggregate. However, due to the limited resources of natural river sand, over-exploitation has caused serious damage to the environment. In recent years, manufactured sand has gradually become a substitute for natural river sand. Manufactured sand is made from mine stone materials, construction waste, or tailings, etc., and has the advantages of wide sources and low cost. However, manufactured sand particles have many edges and corners and a rough surface, resulting in poor water retention of cement mortar, affecting its compactness and strength, and thus reducing durability. In addition, traditional cement mortar has problems such as large dry shrinkage and poor adhesion to old concrete during the repair process, resulting in poor repair effects and being difficult to meet the requirements of high-quality pavement repair.

[0004] In the prior art, although some repair materials improve their performance by adding water-reducing agents, fibers and other admixtures, these improvement measures often fail to fully solve the problems of poor water retention, insufficient strength and durability of manufactured sand. At the same time, the existing materials still need to be improved in terms of construction convenience and rapid repair ability. Therefore, developing an environmentally friendly and efficient pavement repair material has become an urgent technical problem to be solved. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a preparation process of an environmentally friendly quartz powder-containing cement-based pavement repair material, which solves the problems raised in the above background art.

[0006] To achieve the above object, the present invention is realized through the following technical solutions: An environmentally friendly quartz powder-containing cement-based pavement repair material, the material comprises the following raw materials in parts by weight: 167 - 180 parts of cement, 475 - 486 parts of manufactured sand, 50 - 60 parts of quartz powder, 8.35 - 9.62 parts of gypsum, 1 - 3 parts of water-reducing agent, the addition amount of PVC fiber is not more than 1% of the total volume, 230 - 250 parts of water, wherein, the manufactured sand is made from waste quartz stone materials, and the particle size of the quartz powder is between 1 - 20 μm, and the SiO2 content is ≥ 99%.

[0007] Preferably, the cement is 42.5 ordinary Portland cement with an initial setting time > 3 h, a final setting time of 6 - 10 h, a flexural strength of ≥ 6.5 MPa after 28 days, and a compressive strength of ≥ 42.5 MPa. The water reducing agent is a polycarboxylate series high-performance water reducing agent.

[0008] Preferably, the preparation method of the manufactured sand is as follows: The waste quartz stone materials are successively subjected to coarse crushing by a jaw crusher, fine crushing by a cone crusher, screening by a vibrating screen, shaping by a sand making machine, and cleaning by a sand washer to obtain the finished sand, with a fineness modulus of 2.4 - 2.8, a mud content of ≤ 1.0%, and a lump content of ≤ 0.5%.

[0009] Preferably, the preparation method of the quartz stone powder includes the following steps: cleaning, drying, crushing, magnetic separation, pickling, acid removal, drying, grinding, and screening. In the pickling step, a mixed acid solution of hydrochloric acid, sulfuric acid, and oxalic acid is used, the pickling temperature is 70 - 80 °C, and the pickling time is 1 - 2 h.

[0010] Preferably, the gypsum is β-type hemihydrate gypsum, with an addition amount of 3 - 5% of the cement weight, and its fineness passes through a 0.080 mm square hole sieve with a residue of ≤ 10%.

[0011] Preferably, it further includes an antifoaming agent. The antifoaming agent is a silicone-based antifoaming agent, with a dosage of 0.01% - 0.03% of the mixing water weight. The PVC fiber has a length of 6 - 12 mm, a diameter of 0.08 - 0.12 mm, a tensile strength of ≥ 500 MPa, and an elastic modulus of ≥ 2000 MPa.

[0012] A preparation process of an environmentally friendly quartz stone powder-containing cement-based pavement repair material includes the following steps:

[0013] S1. Expose the manufactured sand to sunlight for 48 - 54 h to remove surface moisture, and then screen it with a 5 - 6 mm square hole sieve to remove impurities;

[0014] S2: Add cement, fly ash, manufactured sand, quartz stone powder, and gypsum according to the ratio to a forced mixer and dry mix for 2 - 3 min;

[0015] S3: Slowly add 80% of the mixing water, all the water reducing agent, and the antifoaming agent to the dry-mixed mixture, and stir at a speed of 40 - 60 r / min for 3 - 5 min;

[0016] S4: Slowly add PVC fiber during the stirring process, continue to stir for 2 min, and then increase the speed to 100 - 120 r / min and quickly stir for 1 min;

[0017] S5: Pass the stirred mortar through a 0.63 - 0.72 mm square hole sieve to remove agglomerated fibers and large particles.

[0018] Preferably, in the step S3, the temperature of the mixing water is controlled at 15-25°C, and the water-cement ratio is 0.38-0.42. In the step S4, the PVC fibers are added in three equal amounts, and after each addition, stirring is carried out for 45-50 s before the next addition.

[0019] The present invention provides a preparation process for an environmentally friendly quartz powder-containing cement-based pavement repair material. It has the following beneficial effects:

[0020] 1. By using waste quartz stone materials to prepare machine-made sand and quartz powder, the present invention realizes the resource utilization of construction waste, reduces the exploitation of natural river sand, and reduces the damage to the environment. At the same time, the quartz powder partially replaces the use of cement, reducing the energy consumption and carbon dioxide emissions in the cement production process, which conforms to the environmental protection concept of sustainable development. In addition, processes such as cleaning, magnetic separation, and pickling adopted in the production process further remove impurities, ensuring the purity and performance of the material, and further enhancing the environmental protection value.

[0021] 2. The cement-based pavement repair material prepared by the present invention has high strength and excellent durability. The addition of quartz powder significantly improves the compressive strength and flexural strength of the mortar, and at the same time improves the water retention and density of the material. The addition of PVC fibers effectively prevents the generation of microcracks, enhancing the crack resistance and toughness of the material. In addition, through the optimized preparation process, it ensures the full hydration of the material at a low water-cement ratio, further enhancing the strength and durability of the material, enabling it to meet the long-term use requirements of cement concrete pavement repair.

[0022] 3. The preparation process of the present invention is simple and efficient, and the construction is convenient. By adding PVC fibers in batches and controlling the temperature of the mixing water, the uniformity and fluidity of the material are ensured, facilitating construction operations. The material has the characteristic of rapid setting, can reach the designed strength in a short time, significantly shortens the maintenance time of pavement repair, reduces the traffic interruption time, and improves the use efficiency of the road. In addition, the material has high bond strength and can closely adhere to the old concrete, ensuring the durability and reliability of the repair effect, and is particularly suitable for rapid repair of medium and low traffic flow sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the general flow chart of the preparation process of the present invention;

[0024] Figure 2 is the flow chart of the preparation process of the machine-made sand of the present invention;

[0025] Figure 3 is the flow chart of the preparation process of the quartz powder of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Next, in conjunction with the accompanying drawings of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Embodiment 1:

[0028] Please refer to the attached Figure 1 - attached Figure 3 , the embodiment of the present invention provides an environmentally friendly quartz stone powder-containing cement-based pavement repair material, and the material includes the following raw materials in parts by weight: 167 parts of cement, 475 parts of manufactured sand, 50 parts of quartz stone powder, 8.35 parts of gypsum, 1 part of water reducing agent, the addition amount of PVC fiber is not more than 1% of the total volume, and 230 parts of water. Among them, the manufactured sand is made from waste quartz stone materials, the particle size of the quartz stone powder is 18μm, and the SiO2 content ≥ 99%.

[0029] The cement is 42.5 type ordinary Portland cement, the initial setting time > 3h, the final setting time is 6h, the flexural strength of the cement after 28 days ≥ 6.5MPa, the compressive strength ≥ 42.5MPa, and the water reducing agent is a polycarboxylate-based high-performance water reducing agent.

[0030] The preparation method of the manufactured sand is: the waste quartz stone materials are successively subjected to coarse crushing by a jaw crusher, fine crushing by a cone crusher, screening by a vibrating screen, shaping by a sand making machine, and cleaning by a sand washer to obtain the finished sand, the fineness modulus of which is 2.4, the mud content ≤ 1.0%, and the mud lump content ≤ 0.5%.

[0031] Specifically, the manufactured sand is made from waste quartz stone materials through a series of processing technologies, and the specific steps are as follows:

[0032] Coarse crushing by jaw crusher: The large waste quartz stone materials are preliminarily crushed to reduce their size to a range suitable for further processing.

[0033] Fine crushing by cone crusher: The crushed stone materials after coarse crushing are more finely crushed to make the particle size more uniform.

[0034] Screening by vibrating screen: The sand grains of different particle sizes are separated through a vibrating screen to ensure that the particle size of the final product meets the requirements.

[0035] Shaping by sand making machine: The sand grains are shaped to improve the shape of the sand grains, making them closer to the characteristics of natural river sand and improving their applicability in concrete.

[0036] Cleaning by sand washer: Remove impurities such as soil and stone powder in the sand to ensure the purity of the manufactured sand.

[0037] The preparation method of quartz powder includes the following steps: cleaning, drying, crushing, magnetic separation, pickling, deacidification, drying, grinding and screening. In the pickling step, a mixed acid solution of hydrochloric acid, sulfuric acid and oxalic acid is used. The pickling temperature is 70°C and the pickling time is 1 hour.

[0038] Specifically, the purpose of cleaning: Remove the soil, dust and other impurities on the surface of the quartz stone.

[0039] Process: Use a cleaning agent to preliminarily clean the quartz stone, and then rinse it with a large amount of clear water to ensure the surface is clean.

[0040] The purpose of drying: Remove the moisture on the surface of the quartz stone to prepare for subsequent processing.

[0041] Process: Put the cleaned quartz stone into a drying device and heat it with hot air or infrared rays to dry the surface of the quartz stone.

[0042] The purpose of crushing: Crush the large quartz stone into smaller particles for subsequent processing.

[0043] Process: Use a jaw crusher or a hammer crusher to crush the quartz stone into small pieces, and crush it to a particle size less than 10 mm.

[0044] The purpose of magnetic separation: Remove magnetic impurities in the quartz stone, such as iron filings, etc.

[0045] Process: Pass the crushed quartz stone through a magnetic separation device and use a magnetic field to adsorb and separate the magnetic impurities.

[0046] The purpose of pickling: Remove metal impurities and some non-metal impurities in the quartz stone to improve the purity of the quartz stone.

[0047] Acid solution preparation: Use a mixed acid solution of hydrochloric acid, sulfuric acid and oxalic acid. Among them, hydrochloric acid mainly removes iron, sulfuric acid removes impurities such as calcium and magnesium, and oxalic acid helps to remove organic impurities.

[0048] Pickling conditions: Control the pickling temperature at 70°C, and the pickling time is about 1 hour to ensure that the impurities are fully dissolved.

[0049] Process: Put the quartz stone into a pickling tank, add the prepared acid solution, heat it to 70°C and keep it for 1 hour, and stir continuously during this period to ensure uniform reaction.

[0050] The purpose of deacidification: Neutralize the acidity after pickling to prevent the residual acid solution from affecting subsequent processing.

[0051] Process: Rinse the pickled quartz stone with a large amount of clear water, and then add a 0.05%-0.5% sodium hydroxide solution for neutralization. After keeping the pH value neutral, rinse it again.

[0052] The purpose of drying: Remove the moisture in the quartz stone to prepare for grinding.

[0053] Process: Put the deacidified quartz stone into the drying equipment and dry it until the moisture content is lower than 0.5%.

[0054] Purpose of grinding: Grind the dried quartz stone into fine powder to reach the required particle size.

[0055] Equipment: Use a wheel mill or a ball mill for grinding and control the grinding time to obtain a suitable particle size.

[0056] Purpose of screening: Screen out the quartz stone powder that meets the particle size requirements.

[0057] Process: Screen the ground quartz stone powder through a vibrating screen with a screen hole of 45μm to ensure the uniformity of the final product particle size.

[0058] The gypsum is β-type hemihydrate gypsum, and the addition amount is 3% of the weight of the cement. Its fineness passes through a 0.080mm square hole sieve, and the residue on the sieve ≤ 10%. The defoaming agent is a silicone defoaming agent, and the dosage is 0.01% of the weight of the mixing water. The length of the PVC fiber is 6mm, the diameter is 0.08mm, the tensile strength ≥ 500MPa, and the elastic modulus ≥ 2000MPa.

[0059] Specifically, the type of gypsum is β-type hemihydrate gypsum.

[0060] Addition amount: 3% of the weight of the cement. 3% gypsum can effectively delay the setting time of the cement, enabling construction workers to have sufficient time for operation, and at the same time avoiding construction inconvenience caused by too fast hydration reaction of the cement. At the same time, the particles of this gypsum are very fine and can be evenly distributed in the cement-based material, thus better playing its setting retardation role and improving the uniformity and compactness of the material.

[0061] The type of defoaming agent is a silicone defoaming agent. The main function of the defoaming agent is to eliminate the bubbles generated during the mixing process. The existence of bubbles will reduce the compactness and strength of the material, affecting its durability and service performance. The silicone defoaming agent has good defoaming effect and stability, can effectively prevent the generation and accumulation of bubbles, and ensure the uniformity and quality of the material. Tensile strength ≥ 500MPa, elastic modulus ≥ 2000MPa. These performance indicators indicate that the PVC fiber has high strength and rigidity, can withstand large tensile stresses in the cement-based material, effectively prevent the generation and expansion of cracks, and enhance the overall performance of the material.

[0062] A preparation process of an environmentally friendly cement-based road repair material containing quartz stone powder includes the following steps:

[0063] S1. Expose the manufactured sand to the sun for 48h to remove the surface moisture, and then screen it through a 5mm square hole sieve to remove impurities;

[0064] S2: Add cement, fly ash, manufactured sand, quartz powder, and gypsum into a forced mixer according to the ratio and dry mix for 2 - 3 min;

[0065] S3: Slowly add 80% of the mixing water, all the water - reducing agent, and defoamer into the dry - mixed mixture, and stir at a speed of 40 r / min for 3 min;

[0066] The temperature of the mixing water is controlled at 15°C, and the water - cement ratio is 0.38. In step S4, the PVC fiber is added in three equal amounts. After each addition, stir for 45 s before adding the next time.

[0067] S4: Slowly add PVC fiber during the stirring process, continue to stir for 2 min, then increase the rotation speed to 100 r / min and quickly stir for 1 min;

[0068] S5: Pass the mixed mortar through a 0.63 - mm square - hole sieve to remove agglomerated fibers and large particles.

[0069] In order to verify the performance of the environmentally friendly quartz - powder - containing cement - based pavement repair material and the feasibility of the preparation process of the present invention, we designed the following multiple embodiments. Each embodiment uses different material ratios and construction methods. Through the comparison of performance test data, the advantages of the materials of the present invention in terms of strength, durability, and construction convenience are demonstrated. At the same time, through the comparison with traditional materials, the excellent performance and practical application value of the materials of the present invention are further proved.

[0070] Example 2: Repair cracks by surface treatment method

[0071] Material ratio (parts by weight): Cement: 167 parts, Manufactured sand: 475 parts, Quartz powder: 50 parts

[0072] , Gypsum: 8.35 parts, Water - reducing agent: 1 part, PVC fiber: 0.5% (volume ratio), Defoamer: 0.02% (relative to the weight of the mixing water), Water: 230 parts.

[0073] Preparation process:

[0074] Monitoring before repair: Investigate and monitor the cracks, and record information such as crack width, depth, status, and characteristics.

[0075] Material preparation: Weigh each raw material according to the ratio.

[0076] Add cement, fly ash, manufactured sand, quartz powder, and gypsum into the mixer and dry mix for 2 min.

[0077] Slowly add 80% of the mixing water, water - reducing agent, and defoamer, and stir at a speed of 40 r / min for 3 min.

[0078] Add PVC fibers in three equal amounts, stir for 45 seconds after each addition, and then stir rapidly for 1 minute.

[0079] Repair construction:

[0080] Clean the surface of the crack, remove oil stains and accumulated water, and ensure the surface is dry.

[0081] Apply the prepared mortar evenly on the surface of the crack, with a coating thickness of 2 cm.

[0082] Curing: Cover with a plastic film after repair and cure for 24 hours.

[0083] Inspection and acceptance: Drill core samples to check the grouting effect and test the compressive strength and flexural strength.

[0084] The performance test results are shown in Table 1 below:

[0085] Test Items 1 day 3 days 7 days 28 days Compressive Strength (MPa) 22 35 45 52 Flexural Strength (MPa) 5.8 7.2 8.0 8.5 <![CDATA[Wear resistance (kg / cm 2 )]]> 0.4 0.35 0.3 0.25 Water Absorption Rate (%) 6.2 5.8 5.2 4.8

[0086] Table 1.

[0087] Example 3: Repairing cracks by pressure grouting method

[0088] Material ratio (parts by weight): Cement: 175 parts, Mechanism sand: 480 parts, Quartz stone powder: 55 parts

[0089] , Gypsum: 9 parts, Water reducing agent: 2 parts, PVC fiber: 0.8% (volume ratio), Defoaming agent: 0.03% (relative to the weight of mixing water), Water: 240 parts.

[0090] Preparation process:

[0091] Monitoring before repair: The same as Example 2.

[0092] Material preparation:

[0093] Weigh each raw material according to the proportion.

[0094] Add cement, fly ash, mechanism sand, quartz stone powder, and gypsum to the mixer and dry mix for 3 minutes.

[0095] Slowly add 80% of the mixing water, water reducing agent, and defoaming agent, and stir at a speed of 50 r / min for 4 minutes.

[0096] Add PVC fibers in three equal amounts, stir for 50 seconds after each addition, and then stir rapidly for 1 minute.

[0097] Repair construction:

[0098] Clean the surface of the crack, set up grouting nozzles, and form a sealed cavity.

[0099] Use a grouting pump to inject the mortar into the crack, gradually grouting from bottom to top.

[0100] Curing: The same as Example 2.

[0101] Inspection and acceptance: The same as Example 2.

[0102] The performance test results are shown in Table 2 below:

[0103] Test Items 1 day 3 days 7 days 28 days Compressive Strength (MPa) 25 38 48 55 Flexural Strength (MPa) 6.2 7.5 8.3 8.8 <![CDATA[Wear resistance (kg / cm 2 )]]> 0.38 0.32 0.28 0.22 Water Absorption Rate (%) 5.5 5.0 4.5 4.2

[0104] Table 2.

[0105] Example 4: Repairing cracks by filling and sealing method

[0106] Material ratio (parts by weight): Cement: 180 parts, Mechanism sand: 486 parts, Quartz stone powder: 60 parts

[0107] , Gypsum: 9.62 parts, Water reducing agent: 3 parts, PVC fiber: 1.0% (volume ratio), Defoaming agent: 0.03% (relative to the weight of mixing water), Water: 250 parts

[0108] Preparation process:

[0109] Monitoring before repair: The same as Example 2.

[0110] Material preparation: Weigh each raw material according to the proportion. Add cement, fly ash, mechanism sand, quartz stone powder, and gypsum to the mixer and dry mix for 3 min.

[0111] Slowly add 80% of the mixing water, water reducing agent, and defoaming agent, and stir at a speed of 60 r / min for 5 min.

[0112] Add PVC fiber in three equal amounts, stir for 50 seconds each time after adding, and then stir quickly for 1 min.

[0113] Repair construction:

[0114] Open a "V" - shaped groove with a width of 3 cm and a depth of 3 cm along the crack, and remove the loose materials in the crack.

[0115] Embed the mortar until it is flush with the surface of the original structure.

[0116] Curing: The same as Example 2.

[0117] Inspection and acceptance: The same as Example 2.

[0118] The performance test results are shown in Table 3:

[0119] Test Items 1 day 3 days 7 days 28 days Compressive Strength (MPa) 28 40 50 58 Flexural Strength (MPa) 6.5 7.8 8.5 9.0 <![CDATA[Wear resistance (kg / cm 2 )]]> 0.35 0.3 0.25 0.2 Water Absorption Rate (%) 5.0 4.7 4.3 4.0

[0120] Table 3.

[0121] Comparative example:

[0122] Material ratio (parts by weight): Cement: 167 parts, natural river sand: 475 parts, gypsum: 8.35 parts

[0123] Water reducing agent: 1 part, water: 230 parts

[0124] Preparation process:

[0125] Material preparation: Add cement, natural river sand, and gypsum to a mixer and dry mix for 2 min. Add water and water reducing agent and stir for 3 min.

[0126] Repair construction: The same as Example 2.

[0127] Curing: The same as Example 2.

[0128] Inspection and acceptance: The same as Example 2.

[0129] The performance test results are shown in Table 4:

[0130] Test Items 1 day 3 days 7 days 28 days Compressive Strength (MPa) 18 28 35 40 Flexural Strength (MPa) 5.0 6.0 6.5 7.0 <![CDATA[Wear resistance (kg / cm 2 )]]> 0.55 0.5 0.45 0.4 Water Absorption Rate (%) 7.0 6.5 6.0 5.5

[0131] Table 4.

[0132] Conclusion: By comparing the performance test results of the examples and comparative examples, it can be seen that the environmentally friendly quartz powder-containing cement-based pavement repair material of the present invention is superior to traditional materials in terms of performance indicators such as compressive strength, flexural strength, abrasion resistance, and water absorption. Especially in Example 4, its 28-day compressive strength reaches 58 MPa, which is much higher than 40 MPa of the comparative example, proving that the synergistic effect of quartz powder and manufactured sand significantly improves the performance of the material. In addition, the abrasion resistance and water absorption of the material of the present invention are also significantly better than traditional materials, indicating that it has better durability and water retention. These results fully prove the beneficial effects of the present invention and demonstrate its application potential in the repair of cement concrete pavements.

[0133] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly cement-based pavement repair material containing quartz powder, characterized in that: The material includes the following raw materials in parts by weight: 167-180 parts of cement, 475-486 parts of machine-made sand, 50-60 parts of quartz powder, 8.35-9.62 parts of gypsum, 1-3 parts of water reducer, PVC fiber addition amount not exceeding 1% of the total volume, and 230-250 parts of water, wherein the machine-made sand is made of waste quartz stone, the particle size of the quartz powder is between 1-20 μm, and the SiO2 content is ≥99%.

2. The environmentally friendly cement-based pavement repair material containing quartz powder according to claim 1, characterized in that: The cement is 42.5 type ordinary Portland cement, with an initial setting time of more than 3 hours, a final setting time of 6-10 hours, a 28-day flexural strength of the cement of ≥6.5 MPa, and a compressive strength of ≥42.5 MPa. The water reducer is a polycarboxylate-based high-performance water reducer.

3. The environmentally friendly cement-based pavement repair material containing quartz powder according to claim 1, characterized in that: The method for preparing the machine-made sand comprises the following steps: the waste quartz stone is subjected to coarse crushing by a jaw crusher, fine crushing by a cone crusher, screening by a vibrating screen, shaping by a sand making machine, and cleaning by a sand washing machine to obtain finished sand, wherein the finished sand has a fineness modulus of 2.4-2.8, a mud content of ≤1.0%, and a mud block content of ≤0.5%.

4. The environmentally friendly cement-based pavement repair material containing quartz powder according to claim 1, characterized in that: The preparation method of the quartz powder comprises the following steps: cleaning, drying, crushing, magnetic separation, pickling, deacidification, drying, grinding and screening. In the pickling step, a mixed acid solution of hydrochloric acid, sulfuric acid and oxalic acid is used, the pickling temperature is 70-80° C., and the pickling time is 1-2 hours.

5. The environmentally friendly cement-based pavement repair material containing quartz powder according to claim 1, characterized in that: The gypsum is β-type hemihydrate gypsum, the addition amount is 3-5% of the weight of cement, and the fineness thereof can pass through a 0.080mm square hole sieve, and the sieve residue is ≤10%.

6. The environmentally friendly cement-based pavement repair material containing quartz powder according to claim 1, characterized in that: It also includes a defoamer, which is a silicone defoamer with an amount of 0.01%-0.03% of the weight of the mixing water. The PVC fiber has a length of 6-12mm, a diameter of 0.08-0.12mm, a tensile strength of ≥500MPa, and an elastic modulus of ≥2000MPa.

7. A preparation process of an environmentally friendly cement-based pavement repair material containing quartz powder, applied to an environmentally friendly cement-based pavement repair material containing quartz powder as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Expose the machine-made sand to sunlight for 48-54 hours to remove surface moisture, and then sieve with a 5-6mm square hole sieve to remove impurities; S2: Add cement, fly ash, machine-made sand, quartz powder and gypsum according to the proportion into a forced mixer and dry mix for 2-3 minutes; S3: Slowly add 80% of the mixing water and all the water reducer and defoamer into the dry-mixed mixture, and stir at a speed of 40-60r / min for 3-5min; S4: Slowly add PVC fiber during stirring, continue stirring for 2 minutes, then increase the speed to 100-120r / min and stir rapidly for 1 minute; S5: Pass the mixed mortar through a 0.63-0.72 mm square hole sieve to remove clumped fibers and large particles.

8. The process for preparing an environmentally friendly cement-based pavement repair material containing quartz powder according to claim 7, characterized in that: In the step S3, the temperature of the mixing water is controlled at 15-25°C, and the water-cement ratio is 0.38-0.

42. In the step S4, the PVC fiber is added in three equal amounts, and each addition is stirred for 45-50 seconds before the next addition.

Images