Water-permeable plastic composite pervious concrete and preparation method thereof

Abstract

This invention relates to the field of permeable concrete technology, specifically to a permeable plastic composite permeable concrete, comprising a permeable plastic layer, an interface transition layer, and a permeable concrete layer arranged from top to bottom; wherein, the permeable plastic layer comprises the following components in parts by weight: 700-750 parts TPU granules, 250-300 parts recycled EPDM granules, 300-400 parts titanium dioxide coated aggregate, 80-120 parts phase change microcapsules, and 5-8 parts crosslinking agent; this invention achieves instantaneous water permeability through the high porosity of the permeable plastic layer, capable of withstanding 50mm / h rainstorms; simultaneously, the permeable plastic layer absorbs vehicle noise, and the PET plastic fibers within the permeable concrete layer form stress bridges, inhibiting microcrack propagation and increasing fatigue life to more than twice that of ordinary permeable concrete. Compared with the traditional single structure of permeable concrete, this structure achieves functional zoning synergy.

Description

Technical Field

[0001] This invention relates to the field of permeable concrete technology, specifically to a permeable plastic composite permeable concrete and its preparation method. Background Technology

[0002] Permeable concrete, as a core material for sponge city construction, plays an important role in alleviating urban flooding and replenishing groundwater resources. It is an ecological building material with a continuous porous structure. Its technical principle is that cement paste wrapped on the surface of coarse aggregates bonds with each other to form a honeycomb structure, thereby allowing water to pass through.

[0003] However, traditional permeable concrete adopts a "skeleton-void" structure, and its compressive strength (usually 20-30MPa) is negatively correlated with its permeability coefficient (2-5mm / s). When the porosity is increased to meet the permeability requirements, usually 15-25%, the strength drops significantly, making it difficult to meet the requirements of high-load scenarios such as driveways. Although existing technologies improve the strength by adding silica fume or high-efficiency water-reducing agents, the effect is limited and the cost increases significantly. In view of this, we propose a permeable plastic composite permeable concrete and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings mentioned in the background section and provide a permeable plastic composite permeable concrete and its preparation method.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A permeable plastic composite permeable concrete includes a permeable plastic layer, an interface transition layer, and a permeable concrete layer arranged from top to bottom;

[0007] The permeable plastic layer comprises the following components in parts by weight: 700-750 parts TPU granules, 250-300 parts recycled EPDM granules, 300-400 parts titanium dioxide coated aggregate, 80-120 parts phase change microcapsules, and 5-8 parts crosslinking agent.

[0008] Preferably, the permeable concrete layer comprises the following components in parts by weight: 700-850 parts recycled aggregate and 120-180 parts PET plastic fiber.

[0009] Preferably, the phase change microcapsules are: wall material: melamine-formaldehyde resin; core material: decanoic acid-lauric acid eutectic system, phase change temperature 25-28℃, latent heat of phase change ≥180J / g.

[0010] Preferably, the interface transition layer is treated with oxygen plasma and has a surface roughness Ra = 10-15 μm.

[0011] Preferably, the crosslinking agent is a silane coupling agent.

[0012] A method for preparing permeable plastic composite permeable concrete includes the following steps:

[0013] Step 1: Pre-fabrication of permeable plastic layer: TPU granules and recycled EPDM granules are melt-blended, then phase change microcapsules and titanium dioxide coated aggregates are added, and the mixture is molded to obtain a permeable plastic layer.

[0014] Step 2, Interface Treatment: The surface of the permeable plastic layer is bombarded with oxygen plasma and an epoxy resin-silica sol composite layer is sprayed on.

[0015] Step 3: Pour the permeable concrete layer: Dry mix the recycled aggregate with cement for 60 seconds, add a solution containing PET plastic fiber and wet mix for 90 seconds, then pour it onto the permeable plastic layer.

[0016] Step 4, Composite Curing: Steam curing followed by carbon dioxide curing will produce permeable plastic composite permeable concrete.

[0017] Preferably, the melting and blending temperature in step one is 180-190℃.

[0018] Preferably, the compression molding pressure in step one is 5 MPa and the time is 10 min.

[0019] Preferably, the steam curing parameters in step four are: 60℃, 95%RH, 12h, and the carbon dioxide curing parameters are: 20% concentration, 0.1MPa, 24h.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention achieves instantaneous water permeability through the high porosity of the permeable plastic layer, which can cope with rainstorms of up to 50 mm / h. At the same time, the permeable plastic layer can absorb vehicle noise, and the PET plastic fibers in the permeable concrete layer form stress bridging, inhibiting the propagation of microcracks and increasing the fatigue life to more than twice that of ordinary permeable concrete. Compared with the traditional single structure of permeable concrete, this structure achieves the synergistic effect of functional zones.

[0022] This invention uses TPU granules and recycled EPDM granules as the base material, and adds titanium dioxide coated aggregate. The thickness of the permeable plastic layer is designed to be 15-30mm, with a porosity of 35-45%, forming a highly permeable and purification functional zone. The surface of the permeable plastic layer is treated with plasma to form micropores, which enhances the mechanical bonding force with cement slurry. At the same time, the addition of titanium dioxide coated aggregate activates the photocatalytic reaction under natural light, degrading organic pollutants (such as grease and COD) in the runoff, and improving the pollutant removal rate by more than 40%.

[0023] By adding PET plastic fibers to recycled aggregates and creating a three-dimensional mesh toughening structure through a melt drawing process, the flexural strength is increased by 30% (to over 8MPa) while maintaining a water permeability coefficient of >3mm / s. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The present invention will describe the above technical solution in detail through the following embodiments:

[0026] Example 1

[0027] A permeable plastic composite permeable concrete includes a permeable plastic layer, an interface transition layer, and a permeable concrete layer arranged from top to bottom. The permeable plastic layer is 15-30 mm thick, the interface transition layer is 0.1-0.2 mm thick, and the permeable concrete layer is 120-150 mm thick.

[0028] The permeable plastic layer comprises the following components by weight: 700 parts TPU granules, 250 parts recycled EPDM granules, 300 parts titanium dioxide coated aggregate, 80 parts phase change microcapsules, and 5 parts KH-550 silane coupling agent. The titanium dioxide coated aggregate is plastic aggregate with 8wt% nano titanium dioxide loaded on the surface and activated at 120℃ for 1 hour.

[0029] The permeable concrete layer comprises the following components by weight: 700 parts recycled aggregate and 150 parts PET plastic fiber.

[0030] The phase change microcapsules are: wall material: melamine-formaldehyde resin; core material: decanoic acid-lauric acid eutectic system, phase change temperature 25-28℃, latent heat of phase change ≥180J / g.

[0031] It should be explained that the core of the phase change microcapsule adopts a fatty acid eutectic system (decanoic acid-lauric acid, ratio 3:7), with a phase change temperature of 25-28℃, suitable for cooling road surfaces in summer. The latent heat of phase change is ≥180J / g. It is encapsulated in melamine-formaldehyde resin wall material through in-situ polymerization to form microcapsules with a particle size of 5-15μm and a wall thickness of 0.5-1μm. The effects are: daytime cooling, when the road surface temperature is >28℃, the phase change microcapsules absorb heat and undergo a solid-to-liquid phase change, preventing heat from being transferred downwards; nighttime heat storage, when the temperature is <25℃, the phase change microcapsules release heat and undergo a liquid-to-solid phase change, preventing surface icing in winter; synergistic effect: the addition of phase change microcapsules accounts for 8-12% of the mass of the permeable plastic layer, which can cool the road surface by 8-12℃ during the high-temperature period in summer and extend the melting time of ice and snow by 2-3 times.

[0032] By incorporating magnetic iron oxide nanoparticles (3-5% by weight) into the phase change microcapsule wall material, the microcapsules acquire magnetocaloric response characteristics. In winter, the magnetocaloric effect is activated by an external low-frequency alternating magnetic field (50-100kHz), inducing the phase change material to release heat prematurely and preventing road icing. This function achieves active energy regulation compared to traditional coconut shell charcoal, which only has an adsorption function.

[0033] It should be noted that the TPU particles are sourced from BASF in Germany. 1185A, titanium dioxide coated aggregate is purchased from Shanghai Shuaike Chemical Co., Ltd. as SK-T25.

[0034] A method for preparing permeable plastic composite permeable concrete includes the following steps:

[0035] Step 1: Pre-fabrication of permeable plastic layer: Melt and blend TPU granules and recycled EPDM granules at 180℃, then add phase change microcapsules and titanium dioxide coated aggregate, keep the mixing zone at a low temperature (<100℃) to prevent microcapsule rupture, inject the melt into a steel mold, and mold it at a pressure of 5MPa for 10min to form a permeable plastic layer with pre-set holes, with a hole diameter of 10mm and a spacing of 50mm;

[0036] Step 2, Interface Treatment: The surface of the permeable plastic layer is bombarded with oxygen plasma (300W, 5min) to form micron-sized pits (Ra=10-15μm), and an epoxy resin-silica sol composite layer is sprayed on, which contains surfactants to promote the penetration of cement hydration products.

[0037] Step 3: Pour the permeable concrete layer: Dry mix the recycled aggregate with cement for 60 seconds, add an aqueous solution containing PET plastic fiber and superplasticizer (polycarboxylate, water reduction rate 30%), wet mix for 90 seconds to form a fluid mortar, pour the concrete onto the permeable plastic layer, and use a low-frequency vibration table (frequency 20Hz, time 30s) to make the slurry penetrate into the plastic pores.

[0038] Step 4, Composite Curing: Steam curing (60℃, 95%RH, 12h) followed by carbon dioxide exhaust gas curing (20% concentration, 0.1MPa, 24h) converts calcium hydroxide in the interface zone into calcite, increasing the interface bonding strength by 50%, thus obtaining permeable plastic composite permeable concrete.

[0039] It is important to explain that, before the initial setting of the permeable concrete layer, 1-2 hours after pouring, a pulsed magnetic field with an intensity of 0.5-1T and a frequency of 1Hz is applied. This can activate the heat generation of the iron oxide nanoparticles, promote the early hydration of cement, and induce the directional alignment of PET plastic fibers to form a reinforcing network perpendicular to the load direction. The magnetic field is applied for 30 minutes, so that the concrete reaches 50% of the design strength in 24 hours.

[0040] Example 2

[0041] The only difference between this embodiment and Embodiment 1 is that the phase change microcapsules in this embodiment are 90 portions, while all other conditions are the same.

[0042] Example 3

[0043] The only difference between this embodiment and Embodiment 1 is that the phase change microcapsules in this embodiment are 100 parts, while all other conditions are the same.

[0044] Example 4

[0045] The only difference between this embodiment and Embodiment 1 is that the phase change microcapsules in this embodiment are 120 parts, while all other conditions are the same.

[0046] Comparative Example 1

[0047] The only difference between this comparative example and Example 1 is that phase change microcapsules are not added in this comparative example, while all other conditions are the same.

[0048] Comparative Example 2

[0049] The only difference between this comparative example and Example 1 is that no PET plastic fiber is added in this comparative example, while all other conditions are the same.

[0050] Comparative Example 3

[0051] The only difference between this comparative example and Example 1 is that the phase change microcapsules in this comparative example do not contain magnetic iron oxide nanoparticles in their wall material; all other conditions are the same.

[0052] Test case

[0053] Permeability coefficient test: Refer to the "Technical Specification for Permeable Cement Concrete Pavement" (CJJ / T 135), take a Φ100×100mm cylindrical specimen, keep the water head at 15cm, measure the water permeability within 30s, and calculate the permeability coefficient (mm / s). Simulate rainstorm conditions: test the surface water depth under a rainfall intensity of 50mm / h.

[0054] Flexural strength and fatigue life: 100×100×400mm specimens were prepared according to the "Test Procedures for Cement and Cement Concrete in Highway Engineering" (JTG 3420). Three-point bending loading (span 300mm) was applied at a loading rate of 0.8MPa / s. Fatigue testing: 0.1-0.5MPa stress amplitude, 10Hz frequency; the number of load cycles until crack penetration was recorded.

[0055] Temperature control performance: The specimen (300×300×150mm) was placed in a constant temperature chamber, and the surface was subjected to simulated sunlight (1000W / m²). 2 Infrared lamps are used to monitor the temperature fluctuation at the bottom of the permeable plastic layer within 24 hours. Summer conditions: ambient temperature 35℃ → temperature drop; Winter conditions: record the time for the surface ice layer to completely melt at -5℃ (with or without magnetic field activation).

[0056] Pollutant degradation rate: Prepare simulated runoff wastewater (COD = 200 mg / L, oil concentration 50 mg / L), pass it through the surface of the specimen at a flow rate of 5 L / min, collect the effluent to determine COD and oil residue, and calculate the removal rate;

[0057] Interfacial bond strength: Cut the composite specimen and perform a pull-out test (tensile rate 0.5 mm / min) to record the interfacial failure strength (MPa).

[0058] The specific data are shown in Tables 1 and 2 below:

[0059] Table 1

[0060]

[0061] Table 2

[0062] The data in the table above shows that when the phase change microcapsules in Example 3 are 100 parts, the overall performance is the best, the water permeability coefficient is maintained at 3.5 mm / s, the flexural strength is 8.6 MPa, the summer temperature drop is 11.5℃, and the latent heat utilization rate of phase change is the highest. When the phase change microcapsules are excessive, such as when the phase change microcapsules in Example 3 are 120 parts, it will lead to pore blockage and decreased water permeability.

[0063] In Comparative Example 2, the absence of PET plastic fiber resulted in a sharp 26% drop in the flexural strength of the permeable plastic composite permeable concrete, and a fatigue life of only 180,000 cycles, less than half that of Example 1. This demonstrates that the "three-dimensional bridging" effect of PET plastic fiber significantly inhibits crack propagation.

[0064] In Comparative Example 3, the phase change microcapsules did not contain magnetic iron oxide nanoparticles in their wall material, and could not be activated by a magnetic field at -5°C, resulting in a melting time of >180 min. In contrast, Examples 1-4 shortened the melting time to 25-35 min through the magnetocaloric effect (0.5T magnetic field), achieving active de-icing in winter.

[0065] The titanium dioxide-coated aggregate in the permeable plastic layer increases the COD removal rate to over 75%, compared to only 30% in Comparative Example 1. The interface transition layer is plasma-treated to ensure a bonding strength of ≥2.1 MPa, compared to only 1.4 MPa in Comparative Example 2.

[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A permeable plastic composite permeable concrete, characterized in that, It includes, from top to bottom, a permeable plastic layer, an interface transition layer, and a permeable concrete layer; The permeable plastic layer comprises the following components in parts by weight: 700-750 parts TPU granules, 250-300 parts recycled EPDM granules, 300-400 parts titanium dioxide coated aggregate, 80-120 parts phase change microcapsules, and 5-8 parts crosslinking agent. The permeable concrete layer comprises the following components in parts by weight: 700-850 parts recycled aggregate and 120-180 parts PET plastic fiber; The phase change microcapsule wall material contains magnetic iron oxide nanoparticles.

2. The permeable plastic composite permeable concrete as described in claim 1, characterized in that: The phase change microcapsules are: wall material: melamine-formaldehyde resin; core material: decanoic acid-lauric acid eutectic system, phase change temperature 25-28℃, latent heat of phase change ≥180J / g.

3. The permeable plastic composite permeable concrete as described in claim 1, characterized in that: The interface transition layer is treated with oxygen plasma, and its surface roughness Ra = 10-15 μm.

4. The permeable plastic composite permeable concrete as described in claim 1, characterized in that: The crosslinking agent is a silane coupling agent.

5. A method for preparing permeable plastic composite permeable concrete, applicable to the permeable plastic composite permeable concrete according to any one of claims 1-4, characterized in that: Includes the following steps: Step 1: Pre-fabrication of permeable plastic layer: TPU granules and recycled EPDM granules are melt-blended, then phase change microcapsules and titanium dioxide coated aggregates are added, and the mixture is molded to obtain a permeable plastic layer. Step 2, Interface Treatment: The surface of the permeable plastic layer is bombarded with oxygen plasma and an epoxy resin-silica sol composite layer is sprayed on. Step 3: Pour the permeable concrete layer: Dry mix the recycled aggregate with cement for 60 seconds, add a solution containing PET plastic fiber and wet mix for 90 seconds, then pour it onto the permeable plastic layer. Step 4, Composite Curing: Steam curing followed by carbon dioxide curing will produce permeable plastic composite permeable concrete.

6. The method for preparing permeable plastic composite permeable concrete as described in claim 5, characterized in that: The melting and blending temperature in step one is 180-190℃.

7. The method for preparing permeable plastic composite permeable concrete as described in claim 5, characterized in that: In step one, the compression molding pressure is 5 MPa and the time is 10 min.

8. The method for preparing permeable plastic composite permeable concrete as described in claim 5, characterized in that: The steam curing parameters in step four are: 60℃, 95%RH, 12h, and the carbon dioxide curing parameters are: 20% concentration, 0.1MPa, 24h.

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