Pervious concrete for sponge city pavement and preparation and maintenance method thereof

Abstract

The invention is applicable to the technical field of pervious concrete, and provides pervious concrete for sponge city pavements and a preparation and maintenance method thereof, and the preparation and maintenance method comprises the following steps: preparing materials, uniformly mixing coarse aggregates, pretreating the coarse aggregates, preparing the pervious concrete and maintaining the pervious concrete. According to the preparation method, the coarse aggregate is pretreated, and the coarse aggregate in each stage of particle size range, the cement, the water and the additive are stirred in batches, so that sufficient fusion is realized, the binding power among the coarse aggregate, the cement and the additive is enhanced, the compressive strength of the pervious concrete is improved, and the corrosion resistance is enhanced by adding the mildew preventive. Meanwhile, the pretreatment process is simplified, and practical engineering application is easier. A carbon dioxide curing method is adopted, the carbonization efficiency is improved by utilizing the characteristics of the pervious concrete, high strength is achieved within a short time, and the requirements of sponge cities are met. High-temperature steam curing is not needed, energy consumption and cost are reduced, environmental problems are avoided, and a new direction is provided for reducing industrial carbon dioxide emission.

Description

Technical Field

[0001] The present invention belongs to the technical field of permeable concrete, and in particular relates to a permeable concrete for sponge city pavement and a preparation and maintenance method thereof. Background Art

[0002] In order to improve the water resource management capacity of cities in my country, the concept of sponge city came into being, among which permeable concrete occupies a pivotal position in the construction and development of sponge city. At present, some scholars have studied the mix design, preparation process technology and permeability characteristics of permeable concrete, and found that factors such as preparation standards and poor maintenance conditions are the main reasons for the occurrence of diseases in permeable concrete pavement. In the preparation process of permeable concrete, the traditional concrete preparation method is still used: first, the mix ratio is designed according to the engineering requirements and the performance indicators of concrete; then, materials such as cement, water, crushed stone (coarse aggregate) and admixtures are prepared, and water is added to cement and coarse aggregate to stir until the mixture is uniform, and then transported to the designated construction site, concrete is poured into the formwork, and necessary vibration is carried out to ensure that the concrete is dense; after the vibration is completed, appropriate maintenance work is carried out, such as covering with moisturizing materials, watering, etc., to promote the strength development of concrete; finally, when the permeable concrete reaches a certain strength, the formwork is removed and the concrete surface is polished, painted, etc.

[0003] However, the above-mentioned current permeable concrete preparation technology has the following shortcomings: during the mixing process, the order of adding the various components is not specified. For example, if water is added to the coarse aggregate first and then cement is added, water will enter the gaps in the coarse aggregate. During the concrete mixing process, the water in the coarse aggregate will return to the cement and admixtures, increasing the water-cement ratio of the concrete and reducing the mechanical properties of the concrete. In addition, due to the particularity of the pores and coarse aggregates of permeable concrete, the time required for the molding and curing process is relatively long. If the construction conditions and construction methods cannot meet the requirements of the specifications, the overall strength of the permeable concrete will be low and the mechanical properties will be weak. If constructed in the rainy season, permeable concrete is prone to produce molds, algae and other organisms in a long-term high humidity environment, affecting its strength and appearance.

[0004] In view of the above shortcomings, the present invention proposes a permeable concrete for sponge city pavement and a preparation and maintenance method thereof. Summary of the invention

[0005] The object of the present invention is to provide a permeable concrete for sponge city pavement and a preparation and maintenance method thereof, aiming to solve the problems raised in the above-mentioned background technology.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A permeable concrete for sponge city pavement, comprising the following components: coarse aggregate, cement, water and admixture; the admixture comprises SR reinforcing agent and mildewproof agent; 1m 3 Permeable concrete includes 1649.7 kg coarse aggregate, 390 kg cement, 136.5 kg water and 15.015 kg admixture.

[0008] A method for preparing and maintaining permeable concrete for sponge city pavement according to the above-mentioned method comprises the following steps:

[0009] Step 1: Prepare the ingredients;

[0010] Screening and drying of coarse aggregate;

[0011] Step 2: Evenly mix the coarse aggregate:

[0012] Put the dried coarse aggregate into a concrete mixer and stir until the coarse aggregate is evenly mixed;

[0013] Step 3: Pre-treating coarse aggregate;

[0014] Add a portion of cement, water and admixtures into a concrete mixer containing uniformly mixed coarse aggregates, close the door, and stir until the surface of the coarse aggregates is evenly covered with cement and admixture paste;

[0015] Step 4: Prepare permeable concrete;

[0016] After pre-treating the coarse aggregate, the remaining cement, water and admixtures are added to the concrete mixer at one time, and stirred until the mixture is free of water seepage and uniform, thereby making permeable concrete;

[0017] Step 5: Permeable concrete maintenance;

[0018] The evenly mixed permeable concrete is loaded in layers into the formwork that has been oiled at the bottom. The specimen is transferred into a closed curing box or curing room and filled with carbon dioxide gas. The specimen is demoulded after the curing is completed.

[0019] Furthermore, the specific steps of step 1 are as follows:

[0020] Step 11: Place the 9.5mm, 4.75mm and 2.36mm standard sieves from top to bottom to form a screening tool, place the screening tool on the vibrating screen, and 3 1649.7 kg of coarse aggregate contained in the permeable concrete is poured into a 9.5 mm standard sieve, and the vibrating screen machine is started to sieve the coarse aggregate to obtain coarse aggregate with a particle size range of 2.36-4.75 mm and 4.75-9.5 mm;

[0021] Step 12: Place 30% by mass of coarse aggregate with a particle size of 2.36-4.75 mm and 70% by mass of coarse aggregate with a particle size of 4.75-9.5 mm into an electric heated air drying oven and dry at 100±5°C for 1 hour.

[0022] Furthermore, in step 2, stirring is performed at a speed of 35 r / min for 5 min until the coarse aggregate is evenly mixed.

[0023] Furthermore, the specific steps of step 3 are as follows:

[0024] Step 31: Follow 1m 3 190-200 kg of cement contained in the permeable concrete is added to the concrete mixer filled with the uniformly mixed coarse aggregate, and the door of the mixer is closed;

[0025] Step 32: Start the concrete mixer and stir the mixture of coarse aggregate and cement at a speed of 25 r / min for 2 min until it is evenly mixed;

[0026] Step 33: Follow 1m 3 60-70 kg of water contained in the permeable concrete is added to the concrete mixer containing a uniform mixture of coarse aggregate and cement, and the door of the mixer is closed;

[0027] Step 34: Start the concrete mixer and stir the mixture of coarse aggregate, cement and water at a speed of 35 r / min for 4 min until the surface of the coarse aggregate is evenly covered with cement slurry;

[0028] Step 35: Follow 1m 3 7.5075 kg of admixture contained in the permeable concrete is added to the concrete mixer containing a uniform mixture of coarse aggregate, cement and water, and the door is closed;

[0029] Step 36: Start the concrete mixer and stir the mixture of coarse aggregate, cement, water and admixture at a speed of 35 r / min for 4 minutes until the surface of the coarse aggregate is evenly covered with cement and admixture slurry.

[0030] Furthermore, in step 4, stirring is performed at a speed of 35 r / min for 5 min until the mixture is free of water and is uniform.

[0031] Furthermore, in step 5, the relative humidity in the curing box or curing room is controlled to be 40-70%, the mass fraction of carbon dioxide is 20-100%, and the specimen is subjected to carbon dioxide curing for 6-24 hours.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. Compared with the traditional permeable concrete preparation process, the present invention pre-treats the coarse aggregate, and stirs the coarse aggregate of various particle size ranges with cement, water and admixtures in batches to ensure full fusion, which not only fills the microcracks and pores on the surface of the coarse aggregate, but also greatly reduces the various adverse reactions of cement and admixtures during the hydration process. At the same time, this method enhances the bonding force between the coarse aggregate and the cement and admixture, thereby effectively improving the compressive strength of the permeable concrete. And mildew inhibitors are added to the admixture, so that the permeable concrete has good corrosion resistance. At the same time, the present invention effectively saves the pretreatment time of the coarse aggregate and simplifies the pretreatment process, so it is easier to implement and apply in actual engineering.

[0034] 2. The present invention adopts a carbon dioxide curing method, which rationally utilizes the high porosity and low alkalinity characteristics of permeable concrete, reduces the requirements for concrete pre-curing, and makes the carbonization process more efficient. In a relatively short period of time, the concrete can reach a high degree of carbonization, thereby obtaining a higher strength and meeting the use requirements of permeable pavements in sponge cities. In the process of preparing permeable concrete, the present invention does not require the use of high-temperature steam curing required for conventional precast concrete and consumes a large amount of carbon dioxide, which not only greatly reduces the energy consumption in the preparation process of precast permeable concrete, but also saves engineering costs, avoids the environmental problems caused by subsequent chemical reagent treatment, and provides a feasible direction for reducing industrial tail gas carbon dioxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a flowchart of the method of the present invention.

[0036] Figure 2 It is a flowchart of the material preparation step in the present invention.

[0037] Figure 3 It is a flow chart of the step of pre-treating coarse aggregate in the present invention.

[0038] Figure 4 This is a physical picture of the coarse aggregate used in the present invention.

[0039] Figure 5 Schematic diagram of the structure of the coarse aggregate used in the present invention.

[0040] Figure 6 This is a structural diagram of the coarse aggregate after pretreatment in the present invention.

[0041] Figure 7 This is a physical picture of the coarse aggregate after pretreatment in the present invention.

[0042] Figure 8 It is a structural diagram of the uniformly mixed permeable concrete in the present invention.

[0043] Fig. 9It is a schematic diagram of curing by carbon dioxide curing in a curing box in the present invention.

[0044] In the figure: 1-micro cracks; 2-cement and admixture slurry. DETAILED DESCRIPTION

[0045] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0046] A permeable concrete for sponge city pavement, comprising the following components: coarse aggregate, cement, water and admixture; the admixture comprises SR reinforcing agent and mildewproof agent; 1m 3 Permeable concrete includes 1649.7 kg coarse aggregate, 390 kg cement, 136.5 kg water and 15.015 kg admixture.

[0047] A method for preparing and maintaining the permeable concrete for sponge city pavement as described above, the flow chart of which is as follows Figure 1 As shown, the method comprises the following steps:

[0048] Step 1: Prepare the materials. The specific process is as follows: Figure 2 As shown; the specific steps are as follows:

[0049] Step 11: Place the 9.5mm, 4.75mm and 2.36mm standard sieves from top to bottom to form a screening tool, place the screening tool on the vibrating screen, and 3 1649.7 kg of coarse aggregate contained in the permeable concrete is poured into a 9.5 mm standard sieve, and the vibrating screen machine is started to sieve the coarse aggregate to obtain coarse aggregate with a particle size range of 2.36-4.75 mm and 4.75-9.5 mm;

[0050] Step 12: Put 30% by mass of coarse aggregate with a particle size of 2.36-4.75 mm and 70% by mass of coarse aggregate with a particle size of 4.75-9.5 mm into an electric heating blast drying oven and dry at 100±5°C for 1 hour;

[0051] Step 2: Evenly mix the coarse aggregate:

[0052] Put 1649.7 kg of dried coarse aggregate into a horizontal concrete mixer and stir at a speed of 35 r / min for 5 min until the coarse aggregate is evenly mixed;

[0053] Step 3: Pre-treat the coarse aggregate. The specific process is as follows: Figure 3 As shown; the specific steps are as follows:

[0054] Step 31: Follow 1m 3190-200 kg of cement contained in the permeable concrete is added to the concrete mixer filled with the uniformly mixed coarse aggregate, and the door of the mixer is closed;

[0055] Step 32: Start the concrete mixer and stir the mixture of coarse aggregate and cement at a speed of 25 r / min for 2 min until it is evenly mixed;

[0056] Step 33: Follow 1m 3 60-70 kg of water contained in the permeable concrete is added to the concrete mixer containing a uniform mixture of coarse aggregate and cement, and the door of the mixer is closed;

[0057] Step 34: Start the concrete mixer and stir the mixture of coarse aggregate, cement and water at a speed of 35 r / min for 4 min until the surface of the coarse aggregate is evenly covered with cement slurry;

[0058] Step 35: Follow 1m 3 7.5075 kg of admixture contained in the permeable concrete is added to the concrete mixer containing a uniform mixture of coarse aggregate, cement and water, and the door is closed;

[0059] Step 36: Start the concrete mixer and stir the mixture of coarse aggregate, cement, water and admixture at a speed of 35 r / min for 4 minutes until the surface of the coarse aggregate is evenly covered with cement and admixture slurry 2.

[0060] Step 4: Prepare permeable concrete;

[0061] After pre-treating the coarse aggregate, add the remaining cement, water and admixtures into the concrete mixer at one time and stir at a speed of 35r / min for 5 minutes until the mixture is free of water seepage and uniform, thus making permeable concrete.

[0062] Step 5: Permeable concrete maintenance;

[0063] The uniformly mixed permeable concrete is loaded into the template with oil on the bottom in layers, and the specimen is transferred to a closed curing box or curing room and filled with carbon dioxide gas. The relative humidity in the curing box or curing room is controlled to be 40-70%, and the mass fraction of carbon dioxide is 20-100%. The specimen is cured with carbon dioxide for 6-24 hours; demoulding is performed after the curing is completed. The schematic diagram of curing in the curing box by carbon dioxide curing is shown in the figure. Fig. 9 shown. Fig. 9In the curing box, the CO2 container is used to store and release CO2 into the curing box. After the curing starts, the CO2 in the CO2 container will be released and act on the curing process of the concrete. The pressure control valve is used to control the pressure and flow of the CO2 released from the CO2 container. By adjusting the pressure control valve, it can be ensured that the CO2 concentration and pressure in the curing box remain within the set range. The air compressor is used to provide the necessary air pressure to help the CO2 be evenly distributed in the curing box.

[0064] In the embodiment of the present invention, the coarse aggregate used is shown in the figure below: Figure 4 The structure of coarse aggregate is shown in Figure 5 The structure of the pretreated coarse aggregate is shown in Figure 6 The actual picture of the pretreated coarse aggregate is shown in Figure 7 The structural diagram of the uniformly mixed permeable concrete is shown in Figure 8 As shown. Figure 5 It can be seen that due to the screening and mixing of the coarse aggregate, many microcracks are generated on its surface1, and there are many pores on the surface of the coarse aggregate, resulting in poor performance of the coarse aggregate. Figure 6 , Figure 7 and Figure 8 It can be seen that by pretreating the coarse aggregate, the pores and microcracks 1 on the surface of the coarse aggregate are filled with cement and admixture slurry 2, and the cement and admixture slurry 2 will wrap the coarse aggregate, strengthen the connection between the aggregates, and avoid direct contact between the coarse aggregates during the mixing process, resulting in particle breakage, thereby improving the performance of permeable concrete.

[0065] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0066] Example 1: Preparation of 0.003375m 3 Coarse aggregate cement concrete; according to the designed mix ratio, a total of 1.3kg water, 5.57kg coarse aggregate, 0.04kg admixture and 0.46kg cement are required.

[0067] Step 1: Prepare the ingredients; the specific steps are as follows:

[0068] Step 11: Place a 9.5 mm standard sieve, a 4.75 mm standard sieve, and a 2.36 mm standard sieve from top to bottom to form a screening tool, place the screening tool on a vibrating screen, pour the coarse aggregate into the 9.5 mm standard sieve, start the vibrating screen, and screen the coarse aggregate to obtain 3.9 kg of coarse aggregate with a particle size range of 4.75 to 9.5 mm and 1.67 kg of coarse aggregate with a particle size range of 2.36 to 4.75 mm;

[0069] Step 12: Place 3.9 kg of coarse aggregate with a particle size range of 4.75 to 9.5 mm and 1.67 kg of coarse aggregate with a particle size range of 2.36 to 4.75 mm in a 101-5B electric heating blast drying oven and dry at 100° C. for 1 hour;

[0070] Step 2: Evenly mix the coarse aggregate;

[0071] Put 5.57 kg of dried coarse aggregate into a horizontal concrete mixer and stir at 35 r / min for 5 min until the coarse aggregate is evenly mixed;

[0072] Step 3: Pre-treat coarse aggregate; the specific steps are as follows:

[0073] Step 31: Add 0.23 kg of cement into the concrete mixer containing 5.57 kg of coarse aggregate mixed evenly, and close the door;

[0074] Step 32: Start the concrete mixer and stir the mixture of coarse aggregate and cement at a speed of 25 r / min for 2 min until it is evenly mixed;

[0075] Step 33: Add 0.65 kg of water into the concrete mixer containing the uniform mixture of coarse aggregate and cement, and close the door;

[0076] Step 34: Start the concrete mixer and stir the mixture of coarse aggregate, cement and water at a speed of 35 r / min for 4 min until the surface of the coarse aggregate is evenly covered with cement slurry;

[0077] Step 35: Add 0.02 kg of cementitious material (a mixture of SR enhancer and mildew inhibitor, the same below) into a concrete mixer containing a uniform mixture of coarse aggregate, cement and water, and close the door;

[0078] Step 36: Start the concrete mixer and stir the mixture of coarse aggregate, cement, water and admixture at a speed of 35 r / min for 4 minutes until the surface of the coarse aggregate is evenly covered with cement and admixture slurry 2.

[0079] Step 4: Prepare permeable concrete;

[0080] After pre-treating the coarse aggregate, add the remaining 0.23kg of cement, 0.65kg of water and 0.02kg of binder into the concrete mixer, start the concrete mixer, and stir the mixture at a speed of 35r / min for 5min until the mixture is free of water and uniform, thus making permeable concrete.

[0081] Step 5: Permeable concrete maintenance;

[0082] The evenly mixed permeable concrete is loaded in layers into the formwork that has been oiled at the bottom. The specimens are transferred into a closed curing box or curing room and filled with carbon dioxide gas. The relative humidity in the curing box or curing room is controlled to be 50%, and the mass fraction of carbon dioxide is 60%. The specimens are cured with carbon dioxide for 24 hours; demoulding is performed after the curing is completed.

[0083] Example 2: Preparation of 0.003375m 3 Coarse aggregate cement concrete; according to the designed mix ratio, a total of 1.2kg water, 5.67kg coarse aggregate, 0.04kg admixture and 0.6kg cement are required.

[0084] Step 1: Prepare the ingredients; the specific steps are as follows:

[0085] Step 11: Place a 9.5 mm standard sieve, a 4.75 mm standard sieve and a 2.36 mm standard sieve from top to bottom to form a screening tool, place the screening tool on a vibrating screen, pour the coarse aggregate into the 9.5 mm standard sieve, start the vibrating screen to screen the aggregate, and obtain 3.98 kg of coarse aggregate with a particle size range of 4.75 to 9.5 mm and 1.69 kg of coarse aggregate with a particle size range of 2.36 to 4.75 mm;

[0086] Step 12: 3.98 kg of coarse aggregate with a particle size range of 4.75 to 9.5 mm and 1.69 kg of coarse aggregate with a particle size range of 2.36 to 4.75 mm were placed in a 101-5B electric heating blast drying oven and dried at 100°C for 1 hour;

[0087] Step 2: Evenly mix the coarse aggregate;

[0088] Put 5.67 kg of dried coarse aggregate into a horizontal concrete mixer and stir at 35 r / min for 5 min until the aggregate is evenly mixed;

[0089] Step 3: Pre-treat coarse aggregate; the specific steps are as follows:

[0090] Step 31: Add 0.3 kg of cement into the concrete mixer containing 5.67 kg of coarse aggregate mixed evenly, and close the door;

[0091] Step 32: Start the concrete mixer and stir the mixture of coarse aggregate and cement at a speed of 25 r / min for 2 min until it is evenly mixed;

[0092] Step 33: Add 0.6 kg of water into the concrete mixer containing the uniform mixture of coarse aggregate and cement, and close the door;

[0093] Step 34: Start the concrete mixer and stir the mixture of coarse aggregate, cement and water at a speed of 35 r / min for 4 min until the surface of the coarse aggregate is evenly covered with cement slurry;

[0094] Step 35: Add 0.02 kg of binder into the concrete mixer containing the uniform mixture of coarse aggregate, cement and water, and close the door;

[0095] Step 36: Start the concrete mixer and stir the mixture of coarse aggregate, cement, water and admixture at a speed of 35 r / min for 4 minutes until the surface of the coarse aggregate is evenly covered with cement and admixture slurry 2.

[0096] Step 4: Prepare permeable concrete;

[0097] After pre-treating the coarse aggregate, add the remaining 0.3 kg of cement, 0.6 kg of water and 0.02 kg of binder into the concrete mixer, start the concrete mixer, and stir the mixture at a speed of 35 r / min for 5 min until the mixture is free of water and uniform, thereby making permeable concrete.

[0098] Step 5: Permeable concrete maintenance;

[0099] The evenly mixed permeable concrete is loaded in layers into the formwork that has been oiled at the bottom. The specimens are transferred into a closed curing box or curing room and filled with carbon dioxide gas. The relative humidity in the curing box or curing room is controlled to be 50%, and the mass fraction of carbon dioxide is 60%. The specimens are cured with carbon dioxide for 24 hours; demoulding is performed after the curing is completed.

[0100] Example 3: Preparation of 0.003375m 3 Coarse aggregate cement concrete; according to the designed mix ratio, a total of 1.2kg water, 5.55kg coarse aggregate, 0.04kg admixture and 0.6kg cement are required.

[0101] Step 1: Prepare the ingredients; the specific steps are as follows:

[0102] Step 11: Place a 9.5 mm standard sieve, a 4.75 mm standard sieve, and a 2.36 mm standard sieve from top to bottom to form a screening tool, place the screening tool on a vibrating screen, pour the coarse aggregate into the 9.5 mm standard sieve, start the vibrating screen, and screen the coarse aggregate to obtain 3.9 kg of coarse aggregate with a particle size range of 4.75 to 9.5 mm and 1.65 kg of coarse aggregate with a particle size range of 2.36 to 4.75 mm;

[0103] Step 12: Place 3.9 kg of coarse aggregate with a particle size range of 4.75 to 9.5 mm and 1.65 kg of coarse aggregate with a particle size range of 2.36 to 4.75 mm in a 101-5B electric heating blast drying oven and dry them at 100° C. for 1 hour;

[0104] Step 2: Evenly mix the coarse aggregate;

[0105] Put 5.55 kg of coarse aggregate after drying into a horizontal concrete mixer and stir at 35 r / min for 5 min until the aggregate is evenly mixed;

[0106] Step 3: Pre-treat coarse aggregate; the specific steps are as follows:

[0107] Step 31: Add 0.3 kg of cement into the concrete mixer containing 5.55 kg of coarse aggregate mixed evenly, and close the door;

[0108] Step 32: Start the concrete mixer and stir the mixture of coarse aggregate and cement at a speed of 25 r / min for 2 min until it is evenly mixed;

[0109] Step 33: Add 0.6 kg of water into the concrete mixer containing the uniform mixture of coarse aggregate and cement, and close the door;

[0110] Step 34: Start the concrete mixer and stir the mixture of coarse aggregate, cement and water at a speed of 35 r / min for 4 min until the surface of the coarse aggregate is evenly covered with cement slurry;

[0111] Step 35: Add 0.02 kg of binder into the concrete mixer containing the uniform mixture of coarse aggregate, cement and water, and close the door;

[0112] Step 36: Start the concrete mixer and stir the mixture of coarse aggregate, cement, water and admixture at a speed of 35 r / min for 4 minutes until the surface of the coarse aggregate is evenly covered with cement and admixture slurry 2.

[0113] Step 4: Prepare permeable concrete;

[0114] After pre-treating the coarse aggregate, add the remaining 0.3 kg of cement, 0.6 kg of water and 0.02 kg of binder into the concrete mixer, start the concrete mixer, and stir the mixture at a speed of 35 r / min for 5 min until the mixture is free of water and uniform, thereby making permeable concrete.

[0115] Step 5: Permeable concrete maintenance;

[0116] The evenly mixed permeable concrete is loaded in layers into the formwork that has been oiled at the bottom. The specimens are transferred into a closed curing box or curing room and filled with carbon dioxide gas. The relative humidity in the curing box or curing room is controlled to be 50%, and the mass fraction of carbon dioxide is 60%. The specimens are cured with carbon dioxide for 24 hours; demoulding is performed after the curing is completed.

[0117] The permeable concrete prepared in the above Examples 1 to 3 was made into a cubic specimen of 150 mm×150 mm×150 mm, and a compressive strength test was performed. The test results are shown in Table 1:

[0118] Table 1 Compressive strength test results

[0119]

[0120] As can be seen from Table 1, the permeable concrete prepared and cured by the present invention has a significantly improved 28d compressive strength compared to the test piece that has not been cured with carbon dioxide and has not been added with a mildew inhibitor. Due to the large pore characteristics of the permeable concrete, the significant improvement in its compressive strength can expand its application scenarios. In addition, it can be found that the test piece with the mildew inhibitor has no mildew spots after 28 days of curing, while the test piece that has not been cured with carbon dioxide and has not been added with a mildew inhibitor has mildew spots on some of the test pieces due to long-term curing in a humid environment. It can be found that the curing method of the present invention is very helpful to improve the durability and corrosion resistance of the permeable concrete, which can greatly save engineering costs and improve utilization efficiency.

[0121] The above are only preferred embodiments of the present invention. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These should also be regarded as the protection scope of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A permeable concrete for sponge city pavement, characterized in that: It includes the following components: coarse aggregate, cement, water and admixture; the admixture includes SR reinforcing agent and mildew inhibitor; 1m 3 Permeable concrete includes 1649.7 kg coarse aggregate, 390 kg cement, 136.5 kg water and 15.015 kg admixture.

2. A method for preparing and maintaining permeable concrete for sponge city pavement according to claim 1, characterized in that: The following steps are involved: Step 1: Prepare the ingredients; Screening and drying of coarse aggregate; Step 2: Evenly mix the coarse aggregate: Put the dried coarse aggregate into a concrete mixer and stir until the coarse aggregate is evenly mixed; Step 3: Pre-treating coarse aggregate; Add a portion of cement, water and admixtures into a concrete mixer containing uniformly mixed coarse aggregates, close the door, and stir until the surface of the coarse aggregates is evenly covered with cement and admixture paste; Step 4: Prepare permeable concrete; After pre-treating the coarse aggregate, the remaining cement, water and admixtures are added to the concrete mixer at one time, and stirred until the mixture is free of water seepage and uniform, thereby making permeable concrete; Step 5: Permeable concrete maintenance; The evenly mixed permeable concrete is loaded in layers into the formwork that has been oiled at the bottom. The specimen is transferred into a closed curing box or curing room and filled with carbon dioxide gas. The specimen is demoulded after the curing is completed.

3. The method for preparing and maintaining permeable concrete for sponge city pavement according to claim 2, characterized in that: The specific steps of step 1 are as follows: Step 11: Place the 9.5mm, 4.75mm and 2.36mm standard sieves from top to bottom to form a screening tool, place the screening tool on the vibrating screen, and 3 1649.7 kg of coarse aggregate contained in the permeable concrete is poured into a 9.5 mm standard sieve, and the vibrating screen machine is started to sieve the coarse aggregate to obtain coarse aggregate with a particle size range of 2.36-4.75 mm and 4.75-9.5 mm; Step 12: Place 30% by mass of coarse aggregate with a particle size of 2.36-4.75 mm and 70% by mass of coarse aggregate with a particle size of 4.75-9.5 mm into an electric heated air drying oven and dry at 100±5°C for 1 hour.

4. The method for preparing and maintaining permeable concrete for sponge city pavement according to claim 2, characterized in that: In the step 2, stirring is performed at a speed of 35 r / min for 5 min until the coarse aggregate is evenly mixed.

5. The method for preparing and maintaining permeable concrete for sponge city pavement according to claim 2, characterized in that: The specific steps of step 3 are as follows: Step 31: Follow 1m 3 190-200 kg of cement contained in the permeable concrete is added to the concrete mixer filled with the uniformly mixed coarse aggregate, and the door of the mixer is closed; Step 32: Start the concrete mixer and stir the mixture of coarse aggregate and cement at a speed of 25 r / min for 2 min until it is evenly mixed; Step 33: Follow 1m 3 60-70 kg of water contained in the permeable concrete is added to the concrete mixer containing a uniform mixture of coarse aggregate and cement, and the door of the mixer is closed; Step 34: Start the concrete mixer and stir the mixture of coarse aggregate, cement and water at a speed of 35 r / min for 4 min until the surface of the coarse aggregate is evenly covered with cement slurry; Step 35: Follow 1m 3 7.5075 kg of admixture contained in the permeable concrete is added to the concrete mixer containing a uniform mixture of coarse aggregate, cement and water, and the door is closed; Step 36: Start the concrete mixer and stir the mixture of coarse aggregate, cement, water and admixture at a speed of 35 r / min for 4 minutes until the surface of the coarse aggregate is evenly covered with cement and admixture slurry.

6. The method for preparing and maintaining permeable concrete for sponge city pavement according to claim 2, characterized in that: In step 4, the mixture is stirred at a speed of 35 r / min for 5 min until the mixture is free of water and uniform.

7. The method for preparing and maintaining permeable concrete for sponge city pavement according to claim 2, characterized in that: In step 5, the relative humidity in the curing box or curing room is controlled to be 40-70%, the mass fraction of carbon dioxide is 20-100%, and the test piece is subjected to carbon dioxide curing for 6-24 hours.

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