Garden road pervious concrete and construction method

Abstract

The application discloses a kind of garden road pervious concrete and construction method, belong to concrete technical field.The application is made of the following weight parts of raw materials: cement 100-150 parts, coarse aggregate 300-360 parts, fine aggregate 80-100 parts, modified fiber reinforcing agent 3-4 parts, silica ash 15-25 parts, slag powder 20-30 parts, polycarboxylic acid water reducing agent 2-3 parts, nano composite air entraining agent 0.1-0.2 parts, water 220-240 parts.The concrete is by reasonable design each raw material ratio, optimize pore structure, and add specific modified fiber reinforcing agent, can make pervious concrete keep good water permeability rate simultaneously also have excellent strength, freeze-thaw resistance and fertilizer corrosion resistance characteristics, with good market application prospect.

Description

Technical Field

[0001] This invention belongs to the field of concrete technology, specifically relating to a permeable concrete for garden roads and its construction method. Background Technology

[0002] Permeable concrete (also known as porous concrete or no-fines concrete) is a porous structural material made by mixing coarse aggregates, cementitious materials (such as cement), water, and admixtures in a specific ratio, without adding fine aggregates or only adding a small amount of fine aggregates. Its interior is composed of numerous interconnected pores (porosity typically 15%-30%) formed by point contacts between the aggregates, allowing rainwater to quickly infiltrate into the ground, thus providing both load-bearing capacity and ecological benefits. Due to its unique permeability, permeable concrete is widely used in the following scenarios: sponge city construction, landscape engineering, municipal infrastructure, and some special applications, such as flood control embankments and slope protection projects, enhancing soil stability and promoting water circulation; and sports fields (such as the bottom layer of permeable synthetic running tracks), improving drainage efficiency and safety.

[0003] Permeable concrete effectively alleviates urban flooding and waterlogging problems, and when combined with urban rainwater harvesting systems, it enables the secondary reuse of natural water resources. Therefore, its application in landscaping and garden paths is increasing. However, with its widespread use, permeable concrete is also revealing more and more problems in garden paths. For example, while permeable concrete has good permeability, it is difficult to guarantee high mechanical properties, making it prone to early damage. In cold regions, water seeps into the pores and freezes, causing expansion and potentially leading to cracking of the concrete, resulting in poor freeze-thaw resistance. Fertilizers, pesticides, and other chemicals used in landscaping can corrode cementitious materials, shortening the road's lifespan and reducing its resistance to chemical erosion. Therefore, there is an urgent need to research permeable concrete materials that, while maintaining permeability, possess high strength, good freeze-thaw resistance, and high durability. Summary of the Invention

[0004] The purpose of this invention is to provide a permeable concrete for garden roads. This concrete, through the rational design of the proportions of each raw material, optimization of the pore structure, and the addition of a specific modified fiber reinforcing agent, can maintain good permeability while also possessing excellent strength, freeze-thaw resistance, and resistance to fertilizer corrosion.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A permeable concrete for garden roads is made from the following raw materials in parts by weight: 100-150 parts cement, 300-360 parts coarse aggregate, 80-100 parts fine aggregate, 3-4 parts modified fiber reinforcing agent, 15-25 parts silica fume, 20-30 parts slag powder, 2-3 parts polycarboxylate superplasticizer, 0.1-0.2 parts nano-composite air-entraining agent, and 220-240 parts water.

[0007] Preferably, the modified fiber reinforcing agent is prepared by the following method:

[0008] A. Mix polypropylene imitation steel fiber and carbon nanotubes according to the mass ratio, and then activate with argon plasma for 20 min.

[0009] B. The activated product is immersed in a 5% KH-570 ethanol solution and reacted at 60°C for 2-3 hours. After the reaction is completed, it is dried at 80°C for 1 hour to obtain a pretreated fiber mixture.

[0010] C. Mix deionized water, NaOH, and resorcinol in a certain proportion and stir magnetically until transparent. Slowly add glutaraldehyde solution dropwise at room temperature. After the addition is complete, continue to stir magnetically for 2 hours. Then add butyl-pyridine latex and stir at 600 rpm for 10 minutes until uniform. Then add 25% ammonia water dropwise and adjust the pH to 8.5 to obtain an emulsion.

[0011] D. Immerse the pretreated fiber mixture obtained in step B into the emulsion obtained in step C, stir magnetically at 40°C for 10 min, remove and dry at 80°C for 1 h to obtain the modified fiber reinforcing agent.

[0012] Preferably, in step A, the mass ratio of polypropylene imitation steel fiber to carbon nanotubes is 10:1; and the argon plasma activation conditions are 10kV and 50kHz.

[0013] Preferably, in step C, the mass ratio of deionized water, NaOH, resorcinol, 50% glutaraldehyde solution, and butadiene-pyridine latex is 600:0.2:1:0.6:7; and the solid content of butadiene-pyridine latex is 40%.

[0014] Preferably, the preparation method of the nanocomposite air-entraining agent is as follows:

[0015] (1) Disperse nano-silica in 10% ethanol, sonicate for 30-40 min, then add silane coupling agent, stir at 70°C for 4 h, centrifuge and wash 3 times, and vacuum dry to obtain pretreated nano-silica.

[0016] (2) Add nanocellulose to deionized water and homogenize under high pressure to form a 1wt% transparent gel solution;

[0017] (3) The gel obtained in step (2) and the pretreated nano silica obtained in step (1) are mixed in a mass ratio, ultrasonically dispersed at 40 kHz for 1 h, and then allowed to stand for aging for 24 h to obtain a composite gel material.

[0018] (4) Dilute the composite gel material to a solid content of 0.5 wt%, and then adjust the pH to 9.0 with NaOH solution to obtain the nanocomposite air-entraining agent.

[0019] Preferably, in step (1), the silane coupling agent is KH570, and the mass ratio of nano-silica to KH570 is 3:1.

[0020] Preferably, in step (3), the mass ratio of the gel solution to the pretreated nano-silica is 10:3.

[0021] Preferably, the coarse aggregate is basalt crushed stone, wherein the mass ratio of coarse aggregate with a particle size of 15-20mm and 10-15mm is 2:5; and the fine aggregate is river sand, wherein the mass ratio of fine aggregate with a particle size of 2-3mm and 3.5-4.5mm is 3:7.

[0022] This invention also provides a construction method for permeable concrete for garden roads, comprising the following steps:

[0023] Step 1: Mix coarse aggregate and fine aggregate according to the required particle size ratio to obtain coarse aggregate and fine aggregate respectively;

[0024] Step 2: Prepare the modified fiber reinforcing agent and mix it with coarse and fine aggregates in a mixer.

[0025] Step 3: Continue to add cement, silica fume, slag powder, and polycarboxylate superplasticizer to the mixer, and continue mixing for 3-5 minutes to form a uniform mixture;

[0026] Step 4: Add 80% of the total water to the mixer, stir at 60 rpm for 1-2 minutes, then add the mixture of nano-composite air-entraining agent and the remaining 20% ​​water, stir at 30 rpm for 30-40 seconds, and then discharge the material to obtain permeable concrete for garden roads.

[0027] The modified fiber reinforcing agent of this invention is made of polypropylene imitation steel fiber and carbon nanotubes. The polypropylene imitation steel fiber forms a three-dimensional network structure in concrete, which inhibits the propagation of microcracks through physical "bridging". The addition of carbon nanotubes (mass ratio 10:1) further enhances the stiffness and tensile strength of the fiber, significantly improving the flexural strength and impact resistance of concrete. After the fiber is activated by argon plasma and treated with KH-570 silane coupling agent, active groups (-Si-OH) are generated on the surface, which form chemical bonds with cement hydration products (CSH gel) to reduce interface defects. The butadiene-pyridine latex-resin coating layer (a three-dimensional network structure formed by resorcinol / glutaraldehyde crosslinking) enhances the adhesion between the fiber and the matrix, prevents interface delamination caused by stress concentration, and the pyridine ring in the butadiene-pyridine latex has alkaline resistance, which can resist the erosion of garden fertilizers and pesticides, and improve the durability of permeable concrete. The modified fiber reinforcing agent of the present invention achieves efficient synergy between fiber and cement matrix through a three-step modification process of "plasma activation-silane coupling-resin coating", which significantly improves the mechanical properties of concrete.

[0028] The nanocomposite air-entraining agent used in this invention generates uniformly distributed nanoscale bubbles during stirring. These bubbles are stably encapsulated by a gel network, making them less prone to coalescence and breakage. The "nano-SiO2-cellulose gel" stabilizes the nanoscale bubbles, forming a buffer system against ice expansion pressure and improving the freeze-thaw resistance of concrete. Simultaneously, the stable nanoscale bubbles adhere to the pore walls, forming a hydrophobic layer, reducing the viscous resistance of water on the pore walls and accelerating water flow. Furthermore, nano-SiO2 can fill the nanoscale pores of cement paste, increasing the density of the cement paste matrix and reducing the overflow of slurry into the large pores between aggregates, preventing slurry blockage of the main permeable channels. The nano-cellulose gel improves the toughness of the slurry, indirectly increasing compressive strength. The use of the nanocomposite air-entraining agent in this invention significantly improves the freeze-thaw resistance and mechanical strength of permeable concrete while maintaining its high permeability.

[0029] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention optimizes aggregate gradation to form a composite skeleton of "continuous gradation + discontinuous gradation", and then adds an appropriate amount of silica fume and slag powder to fill part of the cement stone pores through micro-aggregate effect, further optimizing and adjusting the porosity; the rough surface of the modified fiber reinforcing agent provides anchoring points for CSH gel, forming a three-dimensional network structure of "fiber-CSH-aggregate", which synergistically improves mechanical properties; the nanocomposite air-entraining agent introduces uniformly distributed and stable microbubbles through the synergistic effect of nano silica and nano cellulose, which significantly improves freeze-thaw resistance; the two optimize the structure from the macro scale (fiber network) and micro scale (bubbles / pores) respectively, and achieve a triple breakthrough in strength, durability and freeze resistance while ensuring permeability, which is especially suitable for garden road scenarios with high requirements for ecology and durability. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to specific embodiments, but is not limited thereto. In the following embodiments, the cement is ordinary Portland cement, specifically ordinary Portland cement PO 42.5.

[0031] Example 1

[0032] A permeable concrete for garden roads is made from the following raw materials in parts by weight: 100 parts cement, 300 parts coarse aggregate, 80 parts fine aggregate, 3 parts modified fiber reinforcing agent, 15 parts silica fume, 20 parts slag powder, 2 parts polycarboxylate superplasticizer, 0.1 parts nanocomposite air-entraining agent, and 220 parts water.

[0033] The modified fiber reinforcing agent is prepared by the following method:

[0034] A. Polypropylene imitation steel fiber and carbon nanotubes were mixed at a mass ratio of 10:1 and activated with argon plasma for 20 min at 10 kV and 50 kHz.

[0035] B. The activated product is immersed in a 5% KH-570 ethanol solution and reacted at 60°C for 2-3 hours. After the reaction is completed, it is dried at 80°C for 1 hour to obtain a pretreated fiber mixture.

[0036] C. Mix deionized water, NaOH, and resorcinol in a certain proportion and stir magnetically until transparent. Slowly add glutaraldehyde solution dropwise at room temperature. After the addition is complete, continue to stir magnetically for 2 hours. Then add butyl-pyridine latex and stir at 600 rpm for 10 minutes until uniform. Then add 25% ammonia water dropwise and adjust the pH to 8.5 to obtain an emulsion.

[0037] D. Immerse the pretreated fiber mixture obtained in step B into the emulsion obtained in step C, stir magnetically at 40°C for 10 min, remove and dry at 80°C for 1 h to obtain the modified fiber reinforcing agent.

[0038] In step C, the mass ratio of deionized water, NaOH, resorcinol, 50% glutaraldehyde solution, and butadiene-pyridine latex is 600:0.2:1:0.6:7; the solid content of butadiene-pyridine latex is 40%.

[0039] The preparation method of the nanocomposite air-entraining agent is as follows:

[0040] (1) Disperse nano-silica in 10% ethanol, sonicate for 30-40 min, then add silane coupling agent KH570, stir and react at 70℃ for 4 h, centrifuge and wash 3 times, and vacuum dry to obtain pretreated nano-silica; the mass ratio of nano-silica to KH570 is 3:1.

[0041] (2) Add nanocellulose to deionized water and homogenize under high pressure to form a 1wt% transparent gel solution;

[0042] (3) The gel obtained in step (2) and the pretreated nano silica obtained in step (1) are mixed at a mass ratio of 10:3, ultrasonically dispersed at 40kHz for 1 hour, and then allowed to stand for aging for 24 hours to obtain a composite gel material.

[0043] (4) Dilute the composite gel material to a solid content of 0.5 wt%, and then adjust the pH to 9.0 with NaOH solution to obtain the nanocomposite air-entraining agent.

[0044] The coarse aggregate is basalt crushed stone, wherein the mass ratio of coarse aggregate with a particle size of 15-20mm and 10-15mm is 2:5; the fine aggregate is river sand, wherein the mass ratio of fine aggregate with a particle size of 2-3mm and 3.5-4.5mm is 3:7.

[0045] The construction method for the above-mentioned permeable concrete for garden paths includes the following steps:

[0046] Step 1: Mix coarse aggregate and fine aggregate according to the required particle size ratio to obtain coarse aggregate and fine aggregate respectively;

[0047] Step 2: Prepare the modified fiber reinforcing agent and mix it with coarse and fine aggregates in a mixer.

[0048] Step 3: Continue to add cement, silica fume, slag powder, and polycarboxylate superplasticizer to the mixer, and continue mixing for 3-5 minutes to form a uniform mixture;

[0049] Step 4: Add 80% of the total water to the mixer, stir at 60 rpm for 1-2 minutes, then add the mixture of nano-composite air-entraining agent and the remaining 20% ​​water, stir at 30 rpm for 30-40 seconds, and then discharge the material to obtain permeable concrete for garden roads.

[0050] Example 2

[0051] A permeable concrete for garden roads is made from the following raw materials in parts by weight: 150 parts cement, 360 parts coarse aggregate, 100 parts fine aggregate, 4 parts modified fiber reinforcing agent, 25 parts silica fume, 30 parts slag powder, 3 parts polycarboxylate superplasticizer, 0.2 parts nanocomposite air-entraining agent, and 240 parts water.

[0052] The modified fiber reinforcing agent is prepared by the following method:

[0053] A. Polypropylene imitation steel fiber and carbon nanotubes were mixed at a mass ratio of 10:1 and activated with argon plasma for 20 min at 10 kV and 50 kHz.

[0054] B. The activated product is immersed in a 5% KH-570 ethanol solution and reacted at 60°C for 2-3 hours. After the reaction is completed, it is dried at 80°C for 1 hour to obtain a pretreated fiber mixture.

[0055] C. Mix deionized water, NaOH, and resorcinol in a certain proportion and stir magnetically until transparent. Slowly add glutaraldehyde solution dropwise at room temperature. After the addition is complete, continue to stir magnetically for 2 hours. Then add butyl-pyridine latex and stir at 600 rpm for 10 minutes until uniform. Then add 25% ammonia water dropwise and adjust the pH to 8.5 to obtain an emulsion.

[0056] D. Immerse the pretreated fiber mixture obtained in step B into the emulsion obtained in step C, stir magnetically at 40°C for 10 min, remove and dry at 80°C for 1 h to obtain the modified fiber reinforcing agent.

[0057] In step C, the mass ratio of deionized water, NaOH, resorcinol, 50% glutaraldehyde solution, and butadiene-pyridine latex is 600:0.2:1:0.6:7; the solid content of butadiene-pyridine latex is 40%.

[0058] The preparation method of the nanocomposite air-entraining agent is as follows:

[0059] (1) Disperse nano-silica in 10% ethanol, sonicate for 30-40 min, then add silane coupling agent KH570, stir and react at 70℃ for 4 h, centrifuge and wash 3 times, and vacuum dry to obtain pretreated nano-silica; the mass ratio of nano-silica to KH570 is 3:1.

[0060] (2) Add nanocellulose to deionized water and homogenize under high pressure to form a 1wt% transparent gel solution;

[0061] (3) The gel obtained in step (2) and the pretreated nano silica obtained in step (1) are mixed at a mass ratio of 10:3, ultrasonically dispersed at 40kHz for 1 hour, and then allowed to stand for aging for 24 hours to obtain a composite gel material.

[0062] (4) Dilute the composite gel material to a solid content of 0.5 wt%, and then adjust the pH to 9.0 with NaOH solution to obtain the nanocomposite air-entraining agent.

[0063] The coarse aggregate is basalt crushed stone, wherein the mass ratio of coarse aggregate with a particle size of 15-20mm and 10-15mm is 2:5; the fine aggregate is river sand, wherein the mass ratio of fine aggregate with a particle size of 2-3mm and 3.5-4.5mm is 3:7.

[0064] The construction method for the above-mentioned permeable concrete for garden paths includes the following steps:

[0065] Step 1: Mix coarse aggregate and fine aggregate according to the required particle size ratio to obtain coarse aggregate and fine aggregate respectively;

[0066] Step 2: Prepare the modified fiber reinforcing agent and mix it with coarse and fine aggregates in a mixer.

[0067] Step 3: Continue to add cement, silica fume, slag powder, and polycarboxylate superplasticizer to the mixer, and continue mixing for 3-5 minutes to form a uniform mixture;

[0068] Step 4: Add 80% of the total water to the mixer, stir at 60 rpm for 1-2 minutes, then add the mixture of nano-composite air-entraining agent and the remaining 20% ​​water, stir at 30 rpm for 30-40 seconds, and then discharge the material to obtain permeable concrete for garden roads.

[0069] Example 3

[0070] A permeable concrete for garden roads is made from the following raw materials in parts by weight: 120 parts cement, 340 parts coarse aggregate, 90 parts fine aggregate, 3.5 parts modified fiber reinforcing agent, 20 parts silica fume, 25 parts slag powder, 2.5 parts polycarboxylate superplasticizer, 0.15 parts nanocomposite air-entraining agent, and 230 parts water.

[0071] The modified fiber reinforcing agent is prepared by the following method:

[0072] A. Polypropylene imitation steel fiber and carbon nanotubes were mixed at a mass ratio of 10:1 and activated with argon plasma for 20 min at 10 kV and 50 kHz.

[0073] B. The activated product is immersed in a 5% KH-570 ethanol solution and reacted at 60°C for 2-3 hours. After the reaction is completed, it is dried at 80°C for 1 hour to obtain a pretreated fiber mixture.

[0074] C. Mix deionized water, NaOH, and resorcinol in a certain proportion and stir magnetically until transparent. Slowly add glutaraldehyde solution dropwise at room temperature. After the addition is complete, continue to stir magnetically for 2 hours. Then add butyl-pyridine latex and stir at 600 rpm for 10 minutes until uniform. Then add 25% ammonia water dropwise and adjust the pH to 8.5 to obtain an emulsion.

[0075] D. Immerse the pretreated fiber mixture obtained in step B into the emulsion obtained in step C, stir magnetically at 40°C for 10 min, remove and dry at 80°C for 1 h to obtain the modified fiber reinforcing agent.

[0076] In step C, the mass ratio of deionized water, NaOH, resorcinol, 50% glutaraldehyde solution, and butadiene-pyridine latex is 600:0.2:1:0.6:7; the solid content of butadiene-pyridine latex is 40%.

[0077] The preparation method of the nanocomposite air-entraining agent is as follows:

[0078] (1) Disperse nano-silica in 10% ethanol, sonicate for 30-40 min, then add silane coupling agent KH570, stir and react at 70℃ for 4 h, centrifuge and wash 3 times, and vacuum dry to obtain pretreated nano-silica; the mass ratio of nano-silica to KH570 is 3:1.

[0079] (2) Add nanocellulose to deionized water and homogenize under high pressure to form a 1wt% transparent gel solution;

[0080] (3) The gel obtained in step (2) and the pretreated nano silica obtained in step (1) are mixed at a mass ratio of 10:3, ultrasonically dispersed at 40kHz for 1 hour, and then allowed to stand for aging for 24 hours to obtain a composite gel material.

[0081] (4) Dilute the composite gel material to a solid content of 0.5 wt%, and then adjust the pH to 9.0 with NaOH solution to obtain the nanocomposite air-entraining agent.

[0082] The coarse aggregate is basalt crushed stone, wherein the mass ratio of coarse aggregate with a particle size of 15-20mm and 10-15mm is 2:5; the fine aggregate is river sand, wherein the mass ratio of fine aggregate with a particle size of 2-3mm and 3.5-4.5mm is 3:7.

[0083] The construction method for the above-mentioned permeable concrete for garden paths includes the following steps:

[0084] Step 1: Mix coarse aggregate and fine aggregate according to the required particle size ratio to obtain coarse aggregate and fine aggregate respectively;

[0085] Step 2: Prepare the modified fiber reinforcing agent and mix it with coarse and fine aggregates in a mixer.

[0086] Step 3: Continue to add cement, silica fume, slag powder, and polycarboxylate superplasticizer to the mixer, and continue mixing for 3-5 minutes to form a uniform mixture;

[0087] Step 4: Add 80% of the total water to the mixer, stir at 60 rpm for 1-2 minutes, then add the mixture of nano-composite air-entraining agent and the remaining 20% ​​water, stir at 30 rpm for 30-40 seconds, and then discharge the material to obtain permeable concrete for garden roads.

[0088] Comparative Example 1

[0089] A permeable concrete for garden roads, whose raw material composition and preparation method are basically the same as those in Example 1, the only difference being that the modified fiber reinforcing agent is replaced with polypropylene imitation steel fiber.

[0090] Comparative Example 2

[0091] A permeable concrete for garden roads, whose raw material composition and preparation method are basically the same as those in Example 1, the only difference being that the nano-composite air-entraining agent is replaced with a conventional rosin resin-based air-entraining agent.

[0092] Comparative Example 3

[0093] A permeable concrete for garden roads, whose raw material composition and preparation method are basically the same as those in Example 1, the only difference being that the modified fiber reinforcing agent is replaced with ordinary polypropylene imitation steel fiber, and the nanocomposite air-entraining agent is replaced with conventional rosin resin air-entraining agent.

[0094] Comparative Example 4

[0095] A traditional permeable concrete has the following raw material composition: 150 parts cement, 350 parts coarse aggregate (single-grade 10-15mm basalt crushed stone), 2 parts polycarboxylate superplasticizer, and 180 parts water. During construction, all raw materials are directly mixed and stirred before discharging.

[0096] Performance testing

[0097] Test methods and standards

[0098] Permeability coefficient: The permeability rate (mm / s) at a water head of 30cm was measured according to the test method for permeable cement concrete pavement materials in GB / T 25993-2010.

[0099] Mechanical properties: Compressive strength was tested using 100mm cube specimens prepared according to GB / T 50081-2019, after curing for 28 days; flexural strength was tested using prism specimens (100mm×100mm×400mm) prepared according to the same standard. Freeze-thaw resistance was tested using the rapid freezing method (-20℃~20℃ cycle) according to GB / T 50082-2009, and the compressive strength loss rate was tested after 50 cycles.

[0100] Chemical corrosion resistance: The test blocks were immersed in a 5% urea + 2% ammonium sulfate mixed solution (simulating garden fertilizer), and the mass loss rate and compressive strength loss rate were tested after 28 days. The test results are shown in Table 1 below.

[0101] Table 1 Performance Test Results

[0102]

[0103] As can be seen from the results in Table 1 above, the permeability coefficient (3.8-4.1 mm / s) of the permeable concrete obtained in the embodiments of the present invention meets the requirements of garden roads (>2 mm / s), while the 28-day compressive strength and 28-day flexural strength are significantly higher than those of the comparative example. In the freeze-thaw test, the compressive strength loss rate after 50 cycles, the mass loss rate and compressive strength loss rate in the corrosion resistance test after 28 days are all significantly lower than those of the comparative example. This indicates that the permeable concrete prepared by the present invention maintains excellent mechanical properties while maintaining good permeability, and has excellent freeze-thaw resistance and chemical corrosion resistance in low-temperature environments. It is especially suitable for garden road scenarios with high ecological requirements (permeability), high loads (garden vehicles), and severe / corrosive environments (fertilizers, de-icing agents), and has broad market application prospects. This invention utilizes the synergistic effect of "aggregate gradation optimization (discontinuous gradation basalt / river sand) + modified fiber reinforcing agent + nanocomposite air-entraining agent" to form a stable skeleton between coarse and fine aggregates, ensuring permeability channels. The modified fiber reinforcing agent chemically bonds with CSH gel, inhibiting crack propagation and achieving high flexural strength. Simultaneously, the hydroquinone / glutaraldehyde crosslinking network enhances the fiber-matrix interface bonding, improving overall mechanical properties. The nanocomposite air-entraining agent introduces uniformly distributed and stable microbubbles, significantly improving freeze-thaw resistance. The combined effect of the various raw materials in this invention optimizes the structure at both the macroscopic (fiber network) and microscopic (bubbles / pores) scales, achieving a triple breakthrough in strength, durability, and freeze-thaw resistance while ensuring permeability.

[0104] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A permeable concrete for garden roads, characterized in that, It is made from the following raw materials in parts by weight: 100-150 parts cement, 300-360 parts coarse aggregate, 80-100 parts fine aggregate, 3-4 parts modified fiber reinforcing agent, 15-25 parts silica fume, 20-30 parts slag powder, 2-3 parts polycarboxylate superplasticizer, 0.1-0.2 parts nano-composite air-entraining agent, and 220-240 parts water; The modified fiber reinforcing agent is prepared by the following method: A. Mix polypropylene imitation steel fiber and carbon nanotubes according to the mass ratio, and then activate with argon plasma for 20 min. B. The activated product is immersed in a 5% KH-570 ethanol solution and reacted at 60°C for 2-3 hours. After the reaction is completed, it is dried at 80°C for 1 hour to obtain a pretreated fiber mixture. C. Mix deionized water, NaOH, and resorcinol in a certain proportion and stir magnetically until transparent. Slowly add glutaraldehyde solution dropwise at room temperature. After the addition is complete, continue to stir magnetically for 2 hours. Then add butyl-pyridine latex and stir at 600 rpm for 10 minutes until uniform. Then add 25% ammonia water dropwise and adjust the pH to 8.5 to obtain an emulsion. D. Immerse the pretreated fiber mixture obtained in step B into the emulsion obtained in step C, stir magnetically at 40°C for 10 min, remove and dry at 80°C for 1 h to obtain the modified fiber reinforcing agent. The preparation method of the nanocomposite air-entraining agent is as follows: (1) Disperse nano-silica in 10% ethanol, sonicate for 30-40 min, then add silane coupling agent, stir at 70°C for 4 h, centrifuge and wash 3 times, and vacuum dry to obtain pretreated nano-silica. (2) Add nanocellulose to deionized water and homogenize under high pressure to form a 1wt% transparent gel solution; (3) The gel obtained in step (2) and the pretreated nano silica obtained in step (1) are mixed in a mass ratio, ultrasonically dispersed at 40 kHz for 1 h, and then allowed to stand for aging for 24 h to obtain a composite gel material. (4) Dilute the composite gel material to a solid content of 0.5 wt%, and then adjust the pH to 9.0 with NaOH solution to obtain the nanocomposite air-entraining agent.

2. The permeable concrete for garden roads according to claim 1, characterized in that, In step A, the mass ratio of polypropylene imitation steel fiber to carbon nanotubes is 10:1; the argon plasma activation conditions are 10kV and 50kHz.

3. The permeable concrete for garden roads according to claim 1, characterized in that, In step C, the mass ratio of deionized water, NaOH, resorcinol, 50% glutaraldehyde solution, and butadiene-pyridine latex is 600:0.2:1:0.6:7; the solid content of butadiene-pyridine latex is 40%.

4. The permeable concrete for garden paths according to claim 1, characterized in that, In step (1), the silane coupling agent is KH570, and the mass ratio of nano-silica to KH570 is 3:

1.

5. The permeable concrete for garden paths according to claim 1, characterized in that, In step (3), the mass ratio of gel solution to pretreated nano-silica is 10:

3.

6. The permeable concrete for garden paths according to claim 1, characterized in that, The coarse aggregate is basalt crushed stone, wherein the mass ratio of coarse aggregate with a particle size of 15-20mm and 10-15mm is 2:5; the fine aggregate is river sand, wherein the mass ratio of fine aggregate with a particle size of 2-3mm and 3.5-4.5mm is 3:

7.

7. A construction method for permeable concrete for garden roads according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Mix coarse aggregate and fine aggregate according to the required particle size ratio to obtain coarse aggregate and fine aggregate respectively; Step 2: Prepare the modified fiber reinforcing agent and mix it with coarse and fine aggregates in a mixer. Step 3: Continue to add cement, silica fume, slag powder, and polycarboxylate superplasticizer to the mixer, and continue mixing for 3-5 minutes to form a uniform mixture; Step 4: Add 80% of the total water to the mixer, stir at 60 rpm for 1-2 minutes, then add the mixture of nano-composite air-entraining agent and the remaining 20% ​​water, stir at 30 rpm for 30-40 seconds, and then discharge the material to obtain permeable concrete for garden roads.

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