Pervious concrete and preparation method thereof

Abstract

The invention belongs to the technical field of concrete, and provides pervious concrete and a preparation method thereof.The pervious concrete is prepared from cement, modified steel slag, aggregate, basalt fiber, quartz powder, a water reducing agent and water.The hydrophobic modified steel slag is added into the concrete, drainage of water can be accelerated, rapid circulation of accumulated water from the surface to the interior is achieved, and the water permeability of the concrete is improved; and the water-permeable effect is achieved. Basalt fibers are further added into the concrete, the basalt fibers mainly play a role in bridging and connecting, the compactness of the material and the performance of the concrete are improved, meanwhile, the modified steel slag is connected, and the function of a water conveying channel is achieved. The invention also provides the aggregate with particle size grading, and the performance of the concrete is improved through grading of the aggregate and the steel slag. All the raw materials are added according to the principle of a paste method, efficient mixing of the concrete raw materials is achieved, and the uniformity of a system is improved; the method provided by the invention is simple and suitable for large-scale preparation.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete, and particularly to a permeable concrete and a preparation method thereof. Background Art

[0002] Concrete refers to a mixture composed of binder, aggregate, water and admixture, which forms a composite material with an aggregated structure after hardening; due to its rich raw materials, low price, simple production process, excellent performance and other characteristics, concrete has become one of the most important civil engineering materials in modern times. During the use process, it is found that surface water accumulation on concrete has become a common problem. Road surface water accumulation will reduce the friction force, posing a great potential safety hazard to driving; long-term repeated water accumulation on the road surface will cause the road surface to be eroded, the aggregate to fly away, and the road surface structure to be damaged, not only increasing the repair cost, but also affecting driving safety. The simplest solution is to pour the concrete road surface into a structure with a certain slope, but it is very difficult to make the road surface uniform in this way, which affects the traffic effect.

[0003] Therefore, how to solve the problem of road surface water accumulation has become the main research direction in road concrete. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a permeable concrete and a preparation method thereof.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a permeable concrete, which comprises the following raw materials in parts by mass:

[0007] 300 - 500 parts of cement, 40 - 60 parts of modified steel slag, 600 - 800 parts of aggregate, 80 - 120 parts of basalt fiber, 40 - 50 parts of quartz powder, 10 - 15 parts of water reducing agent, 200 - 250 parts of water.

[0008] Preferably, the preparation method of the modified steel slag comprises the following steps:

[0009] (1) After modifying the steel slag in a 1,4-butanediol solution, heat treatment is carried out to obtain hydroxylated steel slag;

[0010] (2) After mixing the hydroxylated steel slag and a hexamethyldisilazane solution, heat treatment is carried out to obtain modified steel slag.

[0011] Preferably, in step (1), the concentration of the 1,4-butanediol solution is 50 - 60%;

[0012] The mass-volume ratio of the steel slag to the 1,4-butanediol solution is 1g:10 - 15mL;

[0013] The particle size of the steel slag described in step (1) is 1 - 2 mm.

[0014] Preferably, the ultrasonic frequency for modification in step (1) is 50 - 60 kHz, the time is 4 - 6 h, and the temperature is 50 - 80 °C;

[0015] The temperature of the heat treatment in step (1) is 400 - 500 °C, and the time is 1 - 3 h.

[0016] Preferably, the concentration of the hexamethyldisilazane solution in step (2) is 30 - 40%;

[0017] The mass - volume ratio of the hydroxylated steel slag to the hexamethyldisilazane solution is 1 g: 8 - 10 mL;

[0018] The rotation speed for mixing in step (2) is 300 - 500 rpm, the temperature is 50 - 80 °C, and the time is 24 - 36 h;

[0019] The temperature of the heat treatment in step (2) is 200 - 300 °C, and the time is 1 - 2 h.

[0020] Preferably, the aggregate includes limestone with a particle size of 3 - 5 mm and limestone with a particle size of 5 - 10 mm;

[0021] The mass ratio of the limestone with a particle size of 3 - 5 mm to the limestone with a particle size of 5 - 10 mm is 3: 4 - 6.

[0022] Preferably, the single - filament diameter of the basalt fiber is 10 - 15 μm, and the length is 2 - 4 mm;

[0023] The specific surface area of the quartz powder is 400 - 450 m 2 / kg.

[0024] The present invention also provides a method for preparing the permeable concrete, comprising the following steps:

[0025] (a) Mix cement and the first part of water, and then add the aggregate for secondary mixing to obtain a mixed system;

[0026] (b) Mix the mixed system, the modified steel slag, and the basalt fiber to obtain a slurry;

[0027] (c) Mix the slurry, the quartz powder, the water - reducing agent, and the remaining water to obtain the permeable concrete.

[0028] Preferably, the mass of the first part of water in step (a) is 40 - 50% of the mass of water;

[0029] The rotation speed for mixing in step (a) is 200 - 300 rpm, and the time is 3 - 5 min;

[0030] The rotation speed of the secondary mixing described in step (a) is 200 - 300 rpm, and the time is 3 - 5 min.

[0031] Preferably, the rotation speed of the mixing described in step (b) is 300 - 500 rpm, and the time is 3 - 5 min;

[0032] The rotation speed of the mixing described in step (c) is 200 - 300 rpm, and the time is 5 - 8 min.

[0033] The present invention provides a permeable concrete, which comprises the following raw materials in parts by mass: 300 - 500 parts of cement, 40 - 60 parts of modified steel slag, 600 - 800 parts of aggregate, 80 - 120 parts of basalt fiber, 40 - 50 parts of quartz powder, 10 - 15 parts of water reducing agent, and 200 - 250 parts of water. In the present invention, the steel slag is modified in a 1,4 - butanediol solution and then subjected to heat treatment to obtain hydroxylated steel slag; the hydroxylated steel slag and a hexamethyldisilazane solution are mixed and then subjected to heat treatment to obtain modified steel slag. By treating the steel slag, a large number of hydroxyl groups are introduced on its surface. After the treated steel slag is heat - treated with the hexamethyldisilazane solution, the surface free energy of the steel slag is reduced, and a large number of methyl groups are grafted; under the action of the low surface free energy and methyl groups, an excellent hydrophobic effect is achieved. Therefore, adding the modified steel slag into the concrete can accelerate the drainage of water, realize the rapid circulation of accumulated water from the surface to the inside, and achieve the permeable effect. The present invention also adds basalt fiber to the concrete. The basalt fiber mainly plays a bridging and connecting role, improves the compactness of the material and the performance of the concrete, and at the same time connects the modified steel slag, playing the role of a water - conveying channel; the present invention also provides an aggregate with a particle size gradation. Through the gradation of the aggregate + steel slag, the performance of the concrete is improved.

[0034] The present invention also provides a preparation method of the concrete. Mix the cement and the first part of water, and then add the aggregate for secondary mixing to obtain a mixed system; mix the mixed system, the modified steel slag and the basalt fiber to obtain a slurry; mix the slurry, the quartz powder, the water reducing agent and the remaining water to obtain the permeable concrete. The present invention adds each raw material according to the principle of the neat - paste method, realizes the efficient mixing of the concrete raw materials, and improves the uniformity of the system; the method provided by the present invention is simple and suitable for large - scale preparation. Specific Embodiments

[0035] The present invention provides a permeable concrete, which comprises the following raw materials in parts by mass:

[0036] 300 - 500 parts of cement, 40 - 60 parts of modified steel slag, 600 - 800 parts of aggregate, 80 - 120 parts of basalt fiber, 40 - 50 parts of quartz powder, 10 - 15 parts of water reducing agent, and 200 - 250 parts of water.

[0037] In the present invention, the mass parts of the cement are preferably 350 to 450 parts, more preferably 360 to 440 parts, and still more preferably 380 to 420 parts.

[0038] In the present invention, the mass parts of the modified steel slag are preferably 45 to 55 parts, more preferably 46 to 54 parts, and still more preferably 48 to 52 parts.

[0039] In the present invention, the mass parts of the aggregate are preferably 650 to 750 parts, more preferably 660 to 740 parts, and still more preferably 680 to 720 parts.

[0040] In the present invention, the mass parts of the basalt fiber are preferably 85 to 115 parts, more preferably 88 to 112 parts, and still more preferably 90 to 105 parts.

[0041] In the present invention, the mass parts of the quartz powder are preferably 42 to 48 parts, more preferably 43 to 47 parts, and still more preferably 44 to 46 parts.

[0042] In the present invention, the mass parts of the water reducing agent are preferably 11 to 14 parts, more preferably 11.5 to 13.5 parts, and still more preferably 12 to 13 parts.

[0043] In the present invention, the mass parts of the water are preferably 205 to 245 parts, more preferably 210 to 240 parts, and still more preferably 220 to 230 parts.

[0044] In the present invention, the cement is P·O42.5 grade cement.

[0045] In the present invention, the preparation method of the modified steel slag comprises the following steps:

[0046] (1) After the steel slag is modified in a 1,4-butanediol solution, heat treatment is carried out to obtain hydroxylated steel slag;

[0047] (2) The hydroxylated steel slag and a hexamethyldisilazane solution are mixed and then heat treated to obtain the modified steel slag.

[0048] In the present invention, in step (1), the concentration of the 1,4-butanediol solution is preferably 50 to 60%, more preferably 52 to 58%, and still more preferably 54 to 56%.

[0049] In the present invention, the mass volume ratio of the steel slag to the 1,4-butanediol solution is preferably 1 g: 10 to 15 mL, more preferably 1 g: 11 to 14 mL, and still more preferably 1 g: 12 to 13 mL.

[0050] In the present invention, the particle size of the steel slag in step (1) is preferably 1 - 2 mm, more preferably 1.2 - 1.8 mm, and still more preferably 1.4 - 1.6 mm.

[0051] In the present invention, the ultrasonic frequency of the modification in step (1) is preferably 50 - 60 kHz, more preferably 52 - 58 kHz, and still more preferably 54 - 56 kHz; the time is preferably 4 - 6 h, more preferably 4.5 - 5.5 h, and still more preferably 4.8 - 5.2 h; the temperature is preferably 50 - 80 °C, more preferably 55 - 75 °C, and still more preferably 60 - 70 °C.

[0052] In the present invention, the temperature of the heat treatment in step (1) is preferably 400 - 500 °C, more preferably 420 - 480 °C, and still more preferably 440 - 460 °C; the time is preferably 1 - 3 h, more preferably 1.5 - 2.5 h, and still more preferably 1.8 - 2.3 h.

[0053] In the present invention, the concentration of the hexamethyldisilazane solution in step (2) is preferably 30 - 40%, more preferably 32 - 38%, and still more preferably 34 - 36%.

[0054] In the present invention, the mass - to - volume ratio of the hydroxylated steel slag to the hexamethyldisilazane solution is preferably 1 g: 8 - 10 mL, more preferably 1 g: 8.5 - 9.5 mL, and still more preferably 1 g: 8.8 - 9 mL.

[0055] In the present invention, the rotation speed of the mixing in step (2) is preferably 300 - 500 rpm, more preferably 350 - 450 rpm, and still more preferably 380 - 420 rpm; the temperature is preferably 50 - 80 °C, more preferably 55 - 75 °C, and still more preferably 60 - 70 °C; the time is preferably 24 - 36 h, more preferably 26 - 34 h, and still more preferably 28 - 32 h.

[0056] In the present invention, the temperature of the heat treatment in step (2) is preferably 200 - 300 °C, more preferably 220 - 280 °C, and still more preferably 240 - 260 °C; the time is preferably 1 - 2 h, more preferably 1.2 - 1.8 h, and still more preferably 1.4 - 1.6 h.

[0057] In the present invention, the aggregate includes limestone with a particle size of 3 - 5 mm and limestone with a particle size of 5 - 10 mm.

[0058] In the present invention, the mass ratio of the limestone with a particle size of 3 - 5 mm to the limestone with a particle size of 5 - 10 mm is preferably 3: 4 - 6, more preferably 3: 4.5 - 5.5, and still more preferably 3: 4.8 - 5.2.

[0059] In the present invention, the single filament diameter of the basalt fiber is preferably 10-15 μm, more preferably 11-14 μm, still more preferably 12-13 μm; the length is preferably 2-4 mm, more preferably 2.5-3.5 mm, still more preferably 2.8-3.2 mm.

[0060] In the present invention, the specific surface area of the quartz powder is preferably 400-450 m 2 / kg, more preferably 410-440 m 2 / kg, still more preferably 420-430 m 2 / kg.

[0061] The present invention also provides a method for preparing the permeable concrete, comprising the following steps:

[0062] (a) Mix cement and the first portion of water, and then add the aggregate for secondary mixing to obtain a mixed system;

[0063] (b) Mix the mixed system, the modified steel slag and the basalt fiber to obtain a slurry;

[0064] (c) Mix the slurry, the quartz powder, the water reducing agent and the remaining water to obtain the permeable concrete.

[0065] In the present invention, the mass of the first portion of water in step (a) is preferably 40-50% of the mass of water, more preferably 42-48%, still more preferably 44-46%.

[0066] In the present invention, the rotation speed of the mixing in step (a) is preferably 200-300 rpm, more preferably 220-280 rpm, still more preferably 240-260 rpm; the time is preferably 3-5 min, more preferably 3.5-4.5 min, still more preferably 3.8-4.2 min.

[0067] In the present invention, the rotation speed of the secondary mixing in step (a) is preferably 200-300 rpm, more preferably 220-280 rpm, still more preferably 240-260 rpm; the time is preferably 3-5 min, more preferably 3.5-4.5 min, still more preferably 3.8-4.2 min.

[0068] In the present invention, the rotation speed of the mixing in step (b) is preferably 300-500 rpm, more preferably 350-450 rpm, still more preferably 380-420 rpm; the time is preferably 3-5 min, more preferably 3.5-4.5 min, still more preferably 3.8-4.2 min.

[0069] In the present invention, the rotation speed of the mixing in step (c) is preferably 200 - 300 rpm, more preferably 220 - 280 rpm, and still more preferably 240 - 260 rpm; the time is preferably 5 - 8 min, more preferably 5.5 - 7.5 min, and still more preferably 6 - 7 min.

[0070] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0071] Example 1

[0072] The raw materials are prepared according to the following parts by mass: 400 parts of cement, 50 parts of modified steel slag, 700 parts of aggregate, 100 parts of basalt fiber, 45 parts of quartz powder, 12 parts of polycarboxylate superplasticizer, and 230 parts of water.

[0073] Among them, the preparation process of the modified steel slag is as follows: Steel slag with a particle size of 1.5 mm and a 1,4 - butanediol solution (concentration of 55%) are mixed at a ratio of 1 g:12 mL, and ultrasonic treatment is carried out for 5 h at 55 kHz and 60 °C. After filtration, the solid is heat - treated in an environment of 450 °C for 2 h to obtain hydroxylated steel slag; the hydroxylated steel slag and a hexamethyldisilazane solution (concentration of 35%) are mixed at a ratio of 1 g:8 mL, stirred at 400 rpm and 70 °C for 24 h, and the filtered solid is heat - treated at 250 °C for 1.5 h to obtain the modified steel slag.

[0074] The cement is P·O42.5 grade cement. The mass ratio of limestone with a particle size of 3 - 5 mm to limestone with a particle size of 5 - 10 mm in the aggregate is 3:5; the single - filament diameter of the basalt fiber is 12 μm and the length is 3 mm; the specific surface area of the quartz powder is 420 m 2 / kg.

[0075] The preparation method of the permeable concrete is as follows: Cement and the first part of water are mixed. The mass of the first part of water is 45% of the total mass of water, and it is stirred at a rotation speed of 250 rpm for 4 min; then the aggregate is added, and it is stirred at 260 rpm for 3 min to obtain a mixed system; the modified steel slag and basalt fiber are added to the mixed system, and it is stirred at a rotation speed of 400 rpm for 3 min to obtain a slurry; the remaining raw materials are added to the slurry, and it is stirred at 260 rpm for 7 min to obtain the permeable concrete.

[0076] Example 2

[0077] The raw materials are prepared according to the following parts by mass: 350 parts of cement, 47 parts of modified steel slag, 720 parts of aggregate, 95 parts of basalt fiber, 41 parts of quartz powder, 13 parts of polycarboxylate superplasticizer, and 225 parts of water.

[0078] Among them, the preparation process of the modified steel slag is as follows: Mix steel slag with a particle size of 2 mm and a 1,4-butanediol solution (concentration of 53%) at a ratio of 1 g: 11 mL, and ultrasonically treat for 4 h under the conditions of 52 kHz and 75 °C. After filtration, place the solid in an environment of 460 °C for heat treatment for 1.2 h to obtain hydroxylated steel slag; Mix the hydroxylated steel slag and a hexamethyldisilazane solution (concentration of 38%) at a ratio of 1 g: 9.5 mL, stir at 420 rpm and 55 °C for 30 h, and place the filtered solid at 300 °C for heat treatment for 2 h to obtain the modified steel slag.

[0079] The cement selected is P·O 42.5 grade cement. The mass ratio of limestone with a particle size of 3 - 5 mm to limestone with a particle size of 5 - 10 mm in the aggregate is 3:6; The single filament diameter of the basalt fiber is 11 μm and the length is 4 mm; The specific surface area of the quartz powder is 410 m 2 / kg.

[0080] The preparation method of the permeable concrete is as follows: Mix the cement and the first part of water, where the mass of the first part of water is 40% of the total mass of water, and stir at a speed of 300 rpm for 5 min; Then add the aggregate and stir at 300 rpm for 5 min to obtain a mixed system; Add the modified steel slag and basalt fiber to the mixed system and stir at a speed of 300 rpm for 5 min to obtain a slurry; Add the remaining raw materials to the slurry and stir at 300 rpm for 8 min to obtain the permeable concrete.

[0081] Example 3

[0082] Prepare the raw materials according to the following mass parts: 460 parts of cement, 58 parts of modified steel slag, 660 parts of aggregate, 82 parts of basalt fiber, 47 parts of quartz powder, 11 parts of polycarboxylate water reducer, and 247 parts of water.

[0083] Among them, the preparation process of the modified steel slag is as follows: Mix steel slag with a particle size of 1 mm and a 1,4-butanediol solution (concentration of 60%) at a ratio of 1 g: 14 mL, and ultrasonically treat for 5.8 h under the conditions of 58 kHz and 50 °C. After filtration, place the solid in an environment of 420 °C for heat treatment for 2 h to obtain hydroxylated steel slag; Mix the hydroxylated steel slag and a hexamethyldisilazane solution (concentration of 40%) at a ratio of 1 g: 8 mL, stir at 350 rpm and 70 °C for 24 h, and place the filtered solid at 220 °C for heat treatment for 1.8 h to obtain the modified steel slag.

[0084] The cement selected is P·O 42.5 grade cement. The mass ratio of limestone with a particle size of 3 - 5 mm to limestone with a particle size of 5 - 10 mm in the aggregate is 3:4; The single filament diameter of the basalt fiber is 14 μm and the length is 2 mm; The specific surface area of the quartz powder is 445 m 2 / kg.

[0085] The preparation method of the permeable concrete is as follows: Mix cement and the first part of water, where the mass of the first part of water is 50% of the total mass of water, and stir at a speed of 260 rpm for 3 min; then add aggregate and stir at 220 rpm for 4 min to obtain a mixed system; add modified steel slag and basalt fiber to the mixed system and stir at a speed of 400 rpm for 4 min to obtain a slurry; add the remaining raw materials to the slurry and stir at 270 rpm for 6 min to obtain the permeable concrete.

[0086] Inject the permeable concrete prepared in Examples 1 to 3 into a mold of 100 mm × 100 mm × 100 mm, form it with a plate vibrator, and after curing for 4 d under natural conditions, test the compressive strength, water permeability coefficient, and porosity of the permeable concrete according to the industry standard of "Permeable Concrete" (JC / T 2558-2020), and the results are recorded in Table 1.

[0087] Table 1 Performance test results

[0088] Compressive strength (MPa) Permeability coefficient (mm / s) Effective porosity (%) Example 1 26.7 8.73 28.6 Example 2 26.5 8.21 27.7 Example 3 27.4 8.42 28.3

[0089] As can be seen from the above examples, the present invention provides a permeable concrete, which uses modified steel slag as a hydrophobic node and basalt fiber as a water-conducting skeleton, and can significantly improve the water permeability coefficient of the concrete, up to 8.73 mm / s at most; under the action of particle size grading and quartz powder, the compressive strength of the concrete still has excellent performance, reaching 27.4 MPa; it is a permeable concrete with excellent comprehensive performance.

[0090] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A permeable concrete, characterized in that, It contains raw materials in the following parts by mass: 300 - 500 parts of cement, 40 - 60 parts of modified steel slag, 600 - 800 parts of aggregate, 80 - 120 parts of basalt fiber, 40 - 50 parts of quartz powder, 10 - 15 parts of water reducing agent, and 200 - 250 parts of water.

2. The permeable concrete according to claim 1, wherein The preparation method of the described modified steel slag includes the following steps: (1) Place the steel slag in a 1,4 - butanediol solution for modification, and then perform heat treatment to obtain hydroxylated steel slag; (2) Mix the hydroxylated steel slag and hexamethyldisilazane solution and then perform heat treatment to obtain modified steel slag.

3. The permeable concrete according to claim 2, wherein In step (1), the concentration of the 1,4 - butanediol solution is 50 - 60%; The mass - to - volume ratio of the steel slag to the 1,4 - butanediol solution is 1g: 10 - 15mL; In step (1), the particle size of the steel slag is 1 - 2mm.

4. The permeable concrete according to claim 3, wherein, In step (1), the ultrasonic frequency of the modification is 50 - 60kHz, the time is 4 - 6h, and the temperature is 50 - 80°C; In step (1), the temperature of the heat treatment is 400 - 500°C, and the time is 1 - 3h.

5. The permeable concrete according to claim 4, wherein, In step (2), the concentration of the hexamethyldisilazane solution is 30 - 40%; The mass - to - volume ratio of the hydroxylated steel slag to the hexamethyldisilazane solution is 1g: 8 - 10mL; In step (2), the rotation speed of the mixing is 300 - 500rpm, the temperature is 50 - 80°C, and the time is 24 - 36h; In step (2), the temperature of the heat treatment is 200 - 300°C, and the time is 1 - 2h.

6. The permeable concrete according to claim 5, characterized in that, The aggregate includes limestone with a particle size of 3 - 5mm and limestone with a particle size of 5 - 10mm; The mass ratio of the limestone with a particle size of 3 - 5mm to the limestone with a particle size of 5 - 10mm is 3: 4 - 6.

7. The permeable concrete according to claim 6, characterized in that, The single - filament diameter of the basalt fiber is 10 - 15μm, and the length is 2 - 4mm; The specific surface area of the quartz powder is 400 to 450 m 2 / kg.

8. The preparation method of the permeable concrete according to any one of claims 1 to 7, characterized in that, It includes the following steps: (a) Mix the cement and the first part of water, and then add the aggregate for secondary mixing to obtain a mixed system; (b) Mix the mixed system, the modified steel slag and the basalt fiber to obtain a slurry; (c) Mix the slurry, the quartz powder, the water reducing agent and the remaining water to obtain the permeable concrete.

9. The preparation method of the permeable concrete according to claim 8, characterized in that, In step (a), the mass of the first part of water is 40 - 50% of the mass of water; In step (a), the rotation speed of the mixing is 200 - 300rpm, and the time is 3 - 5min; In step (a), the rotation speed of the secondary mixing is 200 - 300rpm, and the time is 3 - 5min.

10. The preparation method of the permeable concrete according to claim 9, characterized in that, In step (b), the rotation speed of the mixing is 300 - 500rpm, and the time is 3 - 5min; In step (c), the rotation speed of the mixing is 200 - 300rpm, and the time is 5 - 8min.