CN113354361B

CN113354361B - High-strength pervious concrete and preparation method thereof

Info

Publication number: CN113354361B
Application number: CN202110699918.XA
Authority: CN
Inventors: 谢玲丽
Original assignee: Beijing Minjia Concrete Co ltd
Current assignee: Beijing Minjia Concrete Co ltd
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2022-06-07
Anticipated expiration: 2041-06-23
Also published as: CN113354361A

Abstract

The application relates to the field of building materials, and particularly discloses high-strength pervious concrete and a preparation method thereof. The high-strength permeable concrete comprises the following components in parts by weight: 240 parts of cement, 1300 parts of coarse aggregate, 1600 parts of mineral powder, 70-110 parts of fly ash, 8.5-25.2 parts of additive, 125 parts of water, 5-10 parts of toughening fiber and 10-20 parts of reinforcing agent; each weight part of the reinforcing agent is prepared from the following raw materials in parts by weight: 5-6 parts of alumina, 1-1.25 parts of nano titanium dioxide and 2-2.5 parts of boron carbide; the high-strength pervious concrete has the advantages of being large in water permeability coefficient, high in compressive strength and breaking strength, and high in heat resistance.

Description

High-strength pervious concrete and preparation method thereof

Technical Field

The application relates to the technical field of building materials, in particular to high-strength pervious concrete and a preparation method thereof.

Background

The pervious concrete is a novel concrete produced in order to compensate for the impermeability of common concrete, has water permeability and air permeability, and can relieve urban waterlogging and heat island effect, so that the pervious concrete has received wide attention as an environment-friendly concrete.

In the prior art, Chinese patent application No. 201510805358.6 discloses a lightweight pervious concrete containing ceramsite, and the components and the single dosage ratio of the lightweight pervious concrete are kg/m³The following were used: mixing water 130-³-950kg/m³The compact bulk density is 980kg/m³-1030kg/m³The apparent density is 1700kg/m³-1800kg/m³。

In view of the above related technologies, the inventor believes that the ceramsite made of the coal gangue has light weight and good air permeability, but after the lightweight permeable concrete is hardened, the lightweight permeable concrete has low compressive strength due to more internal pores, and a large number of structural cracks are easy to appear inside the concrete when external force is applied.

Disclosure of Invention

In order to improve the compressive strength and the rupture strength of the pervious concrete, the application provides the high-strength pervious concrete and the preparation method thereof.

In a first aspect, the present application provides a high-strength pervious concrete, which adopts the following technical scheme:

the high-strength pervious concrete comprises the following components in parts by weight: 250 portions of cement 200-containing material, 1600 portions of coarse aggregate 1300-containing material, 70-110 portions of mineral powder, 50-70 portions of fly ash, 8.5-25.2 portions of additive, 125 portions of water 100-containing material, 5-10 portions of toughening fiber and 10-20 portions of reinforcing agent;

each weight part of the reinforcing agent is prepared from the following raw materials in parts by weight: 5-6 parts of alumina, 1-1.25 parts of nano titanium dioxide and 2-2.5 parts of boron carbide.

By adopting the technical scheme, as the alumina, the nano titanium dioxide and the boron carbide are used as reinforcing agents, and the toughening fibers, the mineral powder, the fly ash and other components are added to prepare the high-strength pervious concrete, the boron carbide is lower in hardness than industrial diamond and higher in hardness than silicon carbide, is a superhard material, is large in surface area and high in surface activity, the nano titanium dioxide can increase the amount of crystalline calcium hydroxide in the initial stage of hydration reaction, accelerate the formation of C-S-H gel and improve the harmful pores with small fineness in the body, so that the compressive strength of the concrete is improved, the dosage of the nano titanium dioxide is reasonably controlled, the nano titanium dioxide is prevented from being fully filled into the micropores of the concrete, the porosity is reduced, the permeability coefficient of the concrete is reduced, the alumina and the cement have natural compatibility, and the alumina has extremely high strength and good toughness, the cement has higher activity in the cement hydration reaction, more nano-scale hydration products are bonded on the basis of the original network structure of the cement hardened slurry, and a new compact network structure is formed by secondary hydration reaction, so that the water permeability of the concrete is not influenced while the strength and the toughness of the concrete are improved; in addition, the strength and the crack resistance of the concrete can be enhanced by doping the toughening fibers, and the toughening fibers form a new channel to release vapor pressure after being melted at high temperature, so that the transition loss and even the burst of the compressive strength of the concrete are avoided, and the high-temperature crack resistance of the concrete is effectively improved.

Preferably, the preparation method of the reinforcing agent is as follows: (1) drying boron carbide and nano titanium dioxide, mixing with graphite powder, mixing for 1-2h at 1800 ℃ under 50-60Pa and 1700 ℃ in an inert atmosphere, and cooling to room temperature, wherein the mass ratio of the graphite powder to the nano titanium dioxide is 3.5-4: 1;

(2) adding alumina into deionized water, uniformly stirring, drying at the temperature of 100-;

(3) uniformly mixing the product obtained in the step (1) and the product obtained in the step (2), grinding at the rotating speed of 200-300r/min for 4-5h, preserving the heat at 1450-1500 ℃ and 24-30MPa for 10-15min, cooling to room temperature, crushing and sieving to prepare the reinforcing agent, wherein the mass ratio of the product obtained in the step (1) to the product obtained in the step (2) is 0.1-0.3: 1.

By adopting the technical scheme, under graphite powder and high temperature, boron carbide reduces nano titanium dioxide to form high-purity titanium diboride powder, and because the using amount of the graphite powder is controlled in the reduction reaction, if the carbon content is low, partial titanium oxide can not be reduced all the time, titanium diboride with lower oxygen content is difficult to obtain, and if the carbon content is higher, the synthesized powder contains certain free carbon, so that the titanium diboride is impure; after being calcined, the alumina becomes hard, has special specific surface area, pore volume and pore diameter, and can eliminate diffusion effect in pores; the alpha-alumina spherical particles and the titanium diboride are mixed, under the mechanical grinding, titanium diboride powder is coated on the surfaces of the alpha-alumina spherical particles, after hot-pressing sintering, the combination degree of the titanium diboride and the alpha-alumina spherical particles is increased, so that the improvement of the fracture toughness in the reinforcing agent is mainly derived from the bridging effect of a metal phase, when a crack encounters the titanium diboride in the expansion process, the crack passes through the toughening metal titanium diboride and continues to expand forwards or stops in the metal phase titanium diboride, and at the moment, the titanium diboride is stretched to consume certain energy, thereby improving the fracture toughness of the concrete; after hot pressing, the reinforcing agent is subjected to transverse constraint force, the diameter of the reticular structure unit of the aluminum oxide is reduced, the interface combination degree of the alpha-aluminum oxide spherical particles and the titanium diboride can be improved, and the alpha-aluminum oxide spherical particles and the titanium diboride are prevented from being subjected to interface separation.

Preferably, the alpha-alumina spherical particles in the alumina step (2) are subjected to the following post-treatment:

the alpha-alumina spherical particles are put into a silica sol water solution with the concentration of 20-35 percent and are uniformly mixed, and the mass ratio of the alpha-alumina spherical particles to the silica sol is 1: 0.1-0.2.

By adopting the technical scheme, because the wettability of titanium diboride and alpha-alumina spherical particles is poor, the bonding strength of the alpha-alumina spherical particles and titanium diboride interfaces is not high, and the interface of titanium diboride and alpha-alumina spherical particles is easy to be separated in the concrete fracture process, the alpha-alumina spherical particles are pretreated by using silica sol, silica gel is formed between the alpha-alumina spherical particles and titanium diboride, when the alpha-alumina spherical particles and the titanium diboride are hot-pressed, the silica sol is dissolved and adheres to the titanium diboride, and after the temperature is reduced, the silica sol is solidified between the titanium diboride and the alpha-alumina spherical particles, so that the interface strength between the titanium diboride and the alpha-alumina spherical particles can be increased, and the fracture work generated between the titanium diboride and the alpha-alumina spherical particles due to external force can be relieved, preventing the titanium diboride from separating from the alpha alumina spherical particles.

Preferably, the preparation method of the toughening fiber comprises the following steps:

(1) soaking ramie fibers in a 5% sodium hydroxide solution, performing water bath treatment at 80-85 ℃ for 3-4h, washing to neutrality, and drying to obtain pretreated ramie fibers;

(2) mixing the pretreated ramie fibers, the polypropylene fibers, the graphene and the maleic anhydride grafted POE, mixing and spinning to obtain the toughened fibers, wherein the mass ratio of the polypropylene fibers to the ramie fibers to the graphene is 1:0.3-0.5:0.1-0.3, and the amount of the maleic anhydride grafted POE is 10-15% of that of the polypropylene fibers.

By adopting the technical scheme, the tensile strength and the rigidity of the polypropylene fiber are poor, the ramie fiber has excellent impact property, tensile strength and higher specific modulus, but the surface of the ramie fiber contains a large amount of hydroxyl groups, the polarity is stronger, when the ramie fiber is mixed with the non-polar polypropylene fiber, the interface interaction between the ramie fiber and the non-polar polypropylene fiber is smaller, the binding force is poorer, the ramie fiber is easy to disperse unevenly, and the overall performance is further influenced, therefore, the ramie fiber is pretreated by sodium hydroxide solution, partial pectin, hemicellulose, lignin and other components on the surface of the ramie fiber are removed, the surface smoothness and the specific surface area of the ramie fiber are increased, more mechanical interlocking structures can be formed between the ramie fiber and the polypropylene fiber, then the graphene, the pretreated ramie fiber and the polypropylene fiber are mixed and spun under the action of maleic anhydride grafted POE, and the graphene can form a crosslinking structure with the polypropylene fiber, the tensile property and the crack resistance of the mixture of the polypropylene fibers and the ramie fibers are further improved, the graphene has excellent thermal conductivity, the thermal conductivity of the mixture of the polypropylene fibers and the ramie fibers can be enhanced, heat can be dissipated timely, and the thermal stability is improved, so that the heat resistance of concrete can be improved.

Preferably, the mixing temperature in the step (2) is 190-.

By adopting the technical scheme, the pretreated ramie fibers, the polypropylene fibers and the graphene are mixed for 6-10min at the temperature of 190-200 ℃, and the pretreated ramie fibers, the polypropylene fibers and the graphene can be uniformly mixed, so that the toughened fibers with high tensile strength and good heat resistance are prepared.

Preferably, the admixture is prepared from an air entraining agent, an adhesive and a water reducing agent according to the mass ratio of 1:0.4-0.8: 0.1-0.5.

Through adopting above-mentioned technical scheme, because of mainly depending on binding material to bond each other between the aggregate in the pervious concrete, the adhesive force is relatively weak, when receiving the exogenic action, a large amount of cracks easily appear in inside, use water-reducing agent, the cooperation of adhesive and air entraining agent as the admixture, can increase the dispersion of cement, reduce the water consumption, can also increase the compressive strength of concrete, spherical micro-bubble can be introduced to the air entraining agent, increase the coefficient of permeability of concrete, and the adhesive can increase the surface adhesion properties of aggregate such as concrete slurry and stone, improve the crack resistance of concrete.

Preferably, the adhesive is hydroxypropyl methyl cellulose and polyethylene oxide in a mass ratio of 1: 1-1.5.

By adopting the technical scheme, the hydroxypropyl methyl cellulose can improve the dispersibility of concrete, improve the bonding property of concrete slurry and the surface of stones, improve the strength of the concrete, and after the bonding action between the cement slurry and the stones is enhanced, the sinking of the cement slurry is favorably slowed down, and the water permeability of the concrete is improved.

Preferably, the air entraining agent is prepared from polyacrylic acid and sodium dodecyl benzene sulfonate according to the mass ratio of 2-3: 1.

By adopting the technical scheme, the polyacrylic acid and the sodium dodecyl benzene sulfonate are compatible with each other, the polyacrylic acid has a certain adsorption effect on cement, the fluidity of the concrete is increased, a large amount of uniform spherical micro bubbles are introduced into the sodium dodecyl benzene sulfonate in the raw material process, and the sodium dodecyl benzene sulfonate have synergistic effect, so that the workability of the concrete is improved, and the water permeability and the mechanical strength of the concrete are improved.

Preferably, the coarse aggregate comprises crushed stone and ceramsite with the mass ratio of 1:0.5-0.7, the crushed stone is continuous graded crushed stone with the particle size of 5-20mm, and the apparent density is 2650-³The bulk density is 1700-1750kg/m³The mud content is 0.3-0.5%, and the content of needle-shaped particles is 6-8%; the ceramsite is coal gangue spherical ceramsite with 5-10mm particle size continuous gradation, and the bulk density of the ceramsite is 900-³The compact packing density is 980-1030kg/m³The apparent density is 1700-1800kg/m³。

By adopting the technical scheme, the mud content in the broken stone is proper, the strength of the concrete can be effectively improved, the situation that the concrete strength is lower due to larger pores among aggregates caused by larger particles is avoided, the broken stone and the machine-made sand, the fly ash and the mineral powder form reasonable gradation, the compactness of the concrete can be improved, and the strength and the wear resistance of the concrete are improved; the ceramsite and the macadam are used as the coarse aggregate, so that the compressive strength of the concrete can be enhanced, the stacking treatment problem of the coal gangue is solved, and the ecological environment is obviously promoted.

In a second aspect, the application provides a preparation method of high-strength pervious concrete, which adopts the following technical scheme: a preparation method of high-strength pervious concrete comprises the following steps:

s1, weighing each component for later use;

s2, mixing cement, coarse aggregate, mineral powder and fly ash to prepare a dry mixture;

s3, adding toughening fibers into the dry mixture obtained in the step S2, and uniformly mixing to obtain a premix;

s4, adding 70% of water according to the formula amount into the premix obtained in the step S3, and uniformly stirring to obtain a primary mixed material;

s5, adding an additive and a reinforcing agent into the primary mixed material obtained in the step S4, and uniformly mixing to obtain a mixed material;

and S6, adding the residual amount of water into the mixture obtained in the step S5, and uniformly stirring to obtain the high-strength pervious concrete.

By adopting the technical scheme, the cement, the coarse aggregate, the mineral powder and the fly ash are mixed, then the toughening fiber is added, the components such as water, the additive and the reinforcing agent are added after stirring, and the components are not directly mixed, so that the synergistic effect among the components can be fully exerted, and the prepared concrete not only has higher compressive strength and flexural strength, but also has good water permeability.

In summary, the present application has the following beneficial effects:

1. because the application adopts the alumina, the boron carbide and the nano titanium dioxide as the reinforcing agents and the toughening fibers are doped, the hardness of the boron carbide is high, the specific surface area is large, the nano titanium dioxide can increase the number of calcium hydroxide crystals and improve the compressive strength, the alumina can perform secondary hydration reaction on the basis of the original network structure to form a new compact network structure, the compressive strength of the concrete is improved, the water permeability of the concrete is not influenced, the compressive strength and the crack resistance of the concrete can be improved by adding the toughening fibers, and the heat resistance of the concrete is improved.

2. In the application, preferably, boron carbide and nano titanium dioxide are prepared into titanium diboride powder under hot carbon and high temperature, then the titanium diboride powder and calcined alpha-alumina spherical particles are mechanically ground, the titanium diboride is coated on the surfaces of the alpha-alumina spherical particles, the binding force of the titanium diboride and the alpha-alumina spherical particles is increased under the hot pressing, and the titanium diboride coated on the surfaces of the alpha-alumina spherical particles can consume the energy of crack propagation, so that the fracture toughness of the concrete is improved.

3. In the application, after the aluminum oxide is calcined, the silicon dioxide sol aqueous solution is preferably used for post-treatment, the silicon dioxide sol is formed on the surface of the alpha-aluminum oxide spherical particles, the interface bonding force between the alpha-aluminum oxide spherical particles and the titanium diboride is increased, and the titanium diboride is prevented from being separated from the surface of the alpha-aluminum oxide spherical particles, so that the cracking resistance of the reinforcing agent is reduced.

4. In the application, ramie fibers, graphene and polypropylene fibers are preferably mixed and spun to prepare the toughening fibers, the ramie fibers can improve the tensile strength and toughness of the polypropylene fibers, and the graphene can enhance the tensile strength and heat resistance of the toughening fibers, so that the breaking strength and heat resistance of concrete are improved.

Detailed Description

Preparation examples 1 to 5 of reinforcing agent

In preparation examples 1 to 5, the boron carbide is selected from Hebei Poplar Metal materials, Inc., model No. NYT-B4C-1, and has an average particle size of 60 nm; the nano titanium dioxide is selected from Jiangsu Tianxing new materials Co, the product number is A12; the graphite powder is selected from Guangdong Yongyao graphite technology Limited company, and the model is YY-04; the alumina is selected from Zibo Yinhan special alumina Co., Ltd, model A318.

Preparation example 1: (1) drying 2kg of boron carbide and 1kg of nano titanium dioxide at 110 ℃ for 24h, then mixing with graphite powder, mixing at 50Pa and 1800 ℃ for 2h under an inert atmosphere, and cooling to room temperature, wherein the mass ratio of the graphite powder to the nano titanium dioxide is 3.5: 1;

(2) adding 5kg of alumina into 10kg of deionized water, uniformly stirring, drying at 100 ℃ for 4h, heating to 200 ℃ at a heating rate of 200 ℃/h, preserving heat for 1h, heating to 700 ℃ at a speed of 175 ℃/h, preserving heat for 3h, cooling to room temperature, crushing, and sieving with a 60-mesh sieve to obtain alpha-alumina spherical particles;

(3) and (3) uniformly mixing the product obtained in the step (1) and the product obtained in the step (2), grinding for 5h at the rotating speed of 200r/min, preserving heat at 1450 ℃ and 24MPa for 15min, cooling to room temperature, crushing, and sieving to obtain the reinforcing agent, wherein the mass ratio of the product obtained in the step (1) to the product obtained in the step (2) is 0.1: 1.

Preparation example 2: (1) drying 2.3kg of boron carbide and 1.15kg of nano titanium dioxide at 110 ℃ for 24h, then mixing with graphite powder, mixing at 60Pa and 1700 ℃ for 1h under an inert atmosphere, and cooling to room temperature, wherein the mass ratio of the graphite powder to the nano titanium dioxide is 4: 1;

(2) adding 5.5kg of alumina into 11kg of deionized water, uniformly stirring, drying at 110 ℃ for 3.5h, heating to 220 ℃ at a heating rate of 220 ℃/h, preserving heat for 1h, heating to 750 ℃ at a speed of 190 ℃/h, preserving heat for 3h, cooling to room temperature, crushing, and sieving with a 60-mesh sieve to obtain alpha-alumina spherical particles;

(3) and (3) uniformly mixing the product obtained in the step (1) and the product obtained in the step (2), grinding for 4.5h at the rotating speed of 250r/min, preserving heat for 13min at 1500 ℃ and 27MPa, cooling to room temperature, crushing and sieving to obtain the reinforcing agent, wherein the mass ratio of the product obtained in the step (1) to the product obtained in the step (2) is 0.2:1.

Preparation example 3: (1) drying 2.5kg of boron carbide and 1.25kg of nano titanium dioxide at 110 ℃ for 24h, then mixing with graphite powder, mixing at 55Pa and 1750 ℃ for 1.5h under an inert atmosphere, and cooling to room temperature, wherein the mass ratio of the graphite powder to the nano titanium dioxide is 3.8: 1;

(2) adding 6kg of alumina into 12kg of deionized water, uniformly stirring, drying at 120 ℃ for 3h, heating to 220 ℃ at a heating rate of 220 ℃/h, preserving heat for 1h, heating to 750 ℃ at a speed of 190 ℃/h, preserving heat for 3h, cooling to room temperature, crushing, and sieving with a 60-mesh sieve to obtain alpha-alumina spherical particles;

(3) and (3) uniformly mixing the product obtained in the step (1) and the product obtained in the step (2), grinding at the rotating speed of 300r/min for 4h, preserving heat at 1500 ℃ and 30MPa for 15min, cooling to room temperature, crushing, and sieving to obtain the reinforcing agent, wherein the mass ratio of the product obtained in the step (1) to the product obtained in the step (2) is 0.3: 1.

Preparation example 4: the difference from preparation example 1 is that hot pressing was not performed in step (3).

Preparation example 5: the difference from preparation example 1 is that step (2) was not performed.

Preparation examples 1 to 5 of toughened fibers

Preparation examples 1 to 5 the ramie fibers were selected from Hubei Huachen hemp textile Co., Ltd, No. R48Nm, the polypropylene fibers were selected from Gallery Aoguang and Yinyuan antibacterial Co., Ltd, No. 1038, the graphene was selected from Konli technical materials Co., Ltd, type K10, the maleic anhydride grafted POE was selected from DuPont, U.S.A., and the brand number GR 216.

Preparation example 1: (1) soaking ramie fibers in a sodium hydroxide solution with the concentration of 5%, performing water bath treatment for 4 hours at the temperature of 80 ℃, washing to be neutral, and drying to constant weight at the temperature of 105 ℃ to obtain pretreated ramie fibers, wherein the mass ratio of the ramie fibers to the sodium hydroxide solution is 1: 5;

(2) mixing the pretreated ramie fibers, the polypropylene fibers, the graphene and the maleic anhydride grafted POE, mixing and spinning to obtain the toughened fibers, wherein the mass ratio of the polypropylene fibers to the ramie fibers to the graphene is 1:0.3:0.1, the dosage of the maleic anhydride grafted POE is 10% of that of the polypropylene fibers, the mixing temperature is 190 ℃, the mixing speed is 20r/min, the time is 10min, the spinning temperature in a first zone is 195 ℃, the spinning temperature in a second zone is 215 ℃, the spinning temperature in a third zone is 220 ℃, the spinning temperature in a fourth zone is 228.6 ℃, the spinning temperature in a fifth zone is 230.8 ℃, the spinning speed of a first roller of a drawing roller is 100m/min, the spinning speed of a second roller is 300m/min, the temperature of the first roller is 80 ℃, and the temperature of the second roller is 60 ℃.

Preparation example 2: (1) soaking ramie fibers in a 5% sodium hydroxide solution, performing water bath treatment at 85 ℃ for 3h, washing to be neutral, drying at 105 ℃ to constant weight to obtain pretreated ramie fibers, wherein the mass ratio of the ramie fibers to the sodium hydroxide solution is 1: 5;

(2) mixing the pretreated ramie fibers, the polypropylene fibers, the graphene and the maleic anhydride grafted POE, mixing and spinning to obtain the toughened fibers, wherein the mass ratio of the polypropylene fibers to the ramie fibers to the graphene is 1:0.4:0.2, the dosage of the maleic anhydride grafted POE is 13% of that of the polypropylene fibers, the mixing temperature is 200 ℃, the mixing rotation speed is 25r/min, the time is 10min, the temperature of a first zone is 195 ℃, the temperature of a second zone is 215 ℃, the temperature of a third zone is 220 ℃, the temperature of a fourth zone is 228.6 ℃, the temperature of a fifth zone is 230.8 ℃, the rotation speed of a first roller of a drawing roller is 100m/min, the rotation speed of a two roller is 300m/min, the temperature of a first roller is 80 ℃, and the temperature of a two roller is 60 ℃.

Preparation example 3: (1) soaking ramie fibers in a sodium hydroxide solution with the concentration of 5%, performing water bath treatment for 3 hours at the temperature of 80 ℃, washing to be neutral, and drying to constant weight at the temperature of 105 ℃ to obtain pretreated ramie fibers, wherein the mass ratio of the ramie fibers to the sodium hydroxide solution is 1: 5;

(2) mixing the pretreated ramie fibers, the polypropylene fibers, the graphene and the maleic anhydride grafted POE, mixing and spinning to obtain the toughened fibers, wherein the mass ratio of the polypropylene fibers to the ramie fibers to the graphene is 1:0.5:0.3, the dosage of the maleic anhydride grafted POE is 15% of that of the polypropylene fibers, the mixing temperature is 200 ℃, the mixing rotation speed is 20r/min, the time is 10min, the temperature of a first zone is 195 ℃, the temperature of a second zone is 215 ℃, the temperature of a third zone is 220 ℃, the temperature of a fourth zone is 228.6 ℃, the temperature of a fifth zone is 230.8 ℃, the rotation speed of a first roller of a drawing roller is 100m/min, the rotation speed of a two roller is 300m/min, the temperature of a first roller is 80 ℃, and the temperature of a two roller is 60 ℃.

Preparation example 4: the difference from preparation example 1 is that the ramie fibers were not pretreated with sodium hydroxide solution.

Preparation example 5: the difference from preparation example 1 is that graphene is not added in step (2).

Examples

The sources of the raw materials in the following examples are: the polypropylene fiber is selected from Tokyo Acer sinensis energy-saving technology Limited company, the product number is 1038, the polycarboxylic acid water reducing agent is selected from novel Shangjingfeng Feng building materials Limited company, the product number is JF-JS, the naphthalene water reducing agent is selected from novel Shangjingfeng Feng building materials Limited company, the model number is JF-NX, the hydroxypropyl methyl cellulose is selected from Deling chemical products Limited company in Henan, the model number is 172-1, the polyethylene oxide is selected from Syngnan chemical products Limited company in Zhengzhou, the model number is 6254, the polyacrylic acid is selected from Yangxing chemical products Limited company in Changzhou, the model number is GY-333, and the sodium dodecyl benzene sulfonate is selected from special engineering technology Limited company in Jinan Beiya, and the model number is BYT 20155.

Example 1: the raw material proportion of the high-strength pervious concrete is shown in table 1, and the preparation method of the high-strength pervious concrete comprises the following steps:

s1, weighing the components according to the mixture ratio in the table 1 for later use;

s2, mixing cement, coarse aggregate, mineral powder and fly ash to prepare a dry mixture, wherein the cement is P.O42.5 portland cement, and the coarse aggregate comprises crushed stone and ceramsite in a mass ratio of 1:0.5, and the crushed stone and the ceramsite are crushedThe stone is continuous graded broken stone with particle diameter of 5-20mm, and apparent density of 2650kg/m³Bulk density of 1700kg/m³The mud content is 0.3 percent, and the content of the needle-shaped particles is 6 percent; the ceramsite is coal gangue spherical ceramsite with 5-10mm particle size and continuous gradation, and the bulk density of the ceramsite is 900kg/m³The compact bulk density is 980kg/m³The apparent density is 1700kg/m³The mineral powder is S95 grade mineral powder, and the fly ash is II grade fly ash;

s3, adding toughening fibers into the dry mixture obtained in the step S2, and uniformly mixing to obtain a premix, wherein the toughening fibers are polypropylene fibers;

s5, adding an additive and a reinforcing agent into the primary mixed material obtained in the step S4, and uniformly mixing to obtain a mixed material, wherein the additive is a polycarboxylic acid water reducing agent, and the reinforcing agent is prepared by mixing 5kg of alumina, 1kg of nano titanium dioxide and 2kg of boron carbide;

TABLE 1 component proportions of high-strength pervious concrete in examples 1 to 5

Examples 2 to 5: a high-strength pervious concrete is different from example 1 in that the raw material composition ratios are shown in Table 1.

Example 6: the high-strength pervious concrete is different from the concrete prepared in the embodiment 1 in that the reinforcing agent is prepared from the reinforcing agent prepared in the embodiment 1.

Example 7: the high-strength pervious concrete is different from the concrete in example 1 in that the reinforcing agent is prepared from the reinforcing agent in preparation example 2.

Example 8: the high-strength pervious concrete is different from the concrete in example 1 in that the reinforcing agent is prepared from preparation example 3 of the reinforcing agent.

Example 9: the high-strength pervious concrete is different from the concrete in example 1 in that the reinforcing agent is prepared from the reinforcing agent in preparation example 4.

Example 10: the high-strength pervious concrete is different from the concrete in example 1 in that the reinforcing agent is prepared from preparation example 5 of the reinforcing agent.

Example 11: a high-strength pervious concrete, differing from example 6 in that, in the preparation of the reinforcing agent, the α -alumina spherical particles are subjected to the following post-treatment: the alpha-alumina spherical particles are put into a silica sol aqueous solution with the concentration of 20 percent and are uniformly mixed, the mass ratio of the alpha-alumina spherical particles to the silica sol aqueous solution is 1:0.3, and the silica sol aqueous solution is prepared by mixing the silica sol and water.

Example 12: a high-strength pervious concrete, differing from example 6 in that, in the preparation of the reinforcing agent, the α -alumina spherical particles are subjected to the following post-treatment: the alpha-alumina spherical particles are put into a silica sol aqueous solution with the concentration of 35 percent and are uniformly mixed, the mass ratio of the alpha-alumina spherical particles to the silica sol aqueous solution is 1:0.4, and the silica sol aqueous solution is prepared by mixing silica sol and water.

Example 13: the high-strength pervious concrete is different from the concrete in example 1 in that the toughening fibers are prepared from the toughening fibers in preparation example 1.

Example 14: the high-strength pervious concrete is different from the concrete in example 1 in that the toughening fibers are prepared from the preparation example 2 of the toughening fibers.

Example 15: the high-strength pervious concrete is different from the concrete in example 1 in that the toughening fibers are prepared from the preparation example 3 of the toughening fibers.

Example 16: the high-strength pervious concrete is different from the concrete in example 1 in that the toughening fibers are prepared from the preparation example 4 of the toughening fibers.

Example 17: a high-strength pervious concrete is different from example 1 in that the toughening fibers are prepared from preparation example 5 of the toughening fibers.

Example 18: the high-strength pervious concrete is different from the concrete in example 1 in that the admixture is prepared from an air entraining agent, an adhesive and a water reducing agent according to the mass ratio of 1:0.4:0.1, the water reducing agent is a naphthalene water reducing agent, the adhesive is hydroxypropyl methyl cellulose and polyethylene oxide according to the mass ratio of 1:1, and the air entraining agent is prepared from polyacrylic acid and sodium dodecyl benzene sulfonate according to the mass ratio of 2:1.

Example 19: the high-strength pervious concrete is different from the concrete in example 1 in that the admixture is prepared from an air entraining agent, an adhesive and a water reducing agent according to the mass ratio of 1:0.6:0.3, the water reducing agent is a naphthalene water reducing agent, the adhesive is hydroxypropyl methyl cellulose and polyethylene oxide according to the mass ratio of 1:1.3, and the air entraining agent is prepared from polyacrylic acid and sodium dodecyl benzene sulfonate according to the mass ratio of 2.5: 1.

Example 20: the high-strength pervious concrete is different from the concrete in example 1 in that the admixture is prepared from an air entraining agent, an adhesive and a water reducing agent according to the mass ratio of 1:0.8:0.5, the water reducing agent is a naphthalene water reducing agent, the adhesive is hydroxypropyl methyl cellulose and polyethylene oxide according to the mass ratio of 1:1.5, and the air entraining agent is prepared from polyacrylic acid and sodium dodecyl benzene sulfonate according to the mass ratio of 3: 1.

Example 21: the high-strength pervious concrete is different from the concrete in example 18 in that no air entraining agent is added into the admixture.

Example 22: a high-strength pervious concrete is different from the concrete in example 18 in that no binder is added to the admixture.

Example 23: the high-strength pervious concrete is different from the concrete in example 1 in that the reinforcing agent is prepared from the reinforcing agent in preparation example 1, and the alpha-alumina spherical particles are subjected to the following post-treatment when the reinforcing agent is prepared: putting the alpha-alumina spherical particles into a silica sol aqueous solution with the concentration of 20%, and uniformly mixing, wherein the mass ratio of the alpha-alumina spherical particles to the silica sol is 1:0.1, and the silica sol aqueous solution is prepared by mixing the silica sol and water; the toughening fiber is prepared from the preparation example 1 of the toughening fiber; the additive is prepared from a water reducing agent, an adhesive and an air entraining agent according to the mass ratio of 1:0.4:0.1, the water reducing agent is a naphthalene water reducing agent, the adhesive is hydroxypropyl methyl cellulose and polyethylene oxide according to the mass ratio of 1:1, and the air entraining agent is prepared from polyacrylic acid and sodium dodecyl benzene sulfonate according to the mass ratio of 2:1.

Comparative example

Comparative example 1: the high-strength pervious concrete is different from the concrete in example 1 in that toughening fibers are not added in the raw material components.

Comparative example 2: the high-strength pervious concrete is different from the concrete in example 1 in that alumina is not added in the reinforcing agent.

Comparative example 3: the difference between the high-strength pervious concrete and the concrete in example 1 is that boron carbide is not added in the reinforcing agent.

Comparative example 4: the high-strength pervious concrete is different from the concrete in example 1 in that nano titanium dioxide is not added into a reinforcing agent.

Comparative example 5: a high-strength pervious concrete, which is different from the concrete of example 1 in that the reinforcing agent of the application is replaced by an equal amount of a commercially available reinforcing agent selected from the group consisting of Mimeji Seiki architecture repair technology, Inc. in Beijing, model number Z-6.

Comparative example 6: the high-strength heavy slag pervious concrete comprises the following raw materials in parts by weight: 225 parts of portland cement, 1450 parts of coarse aggregate, 80 parts of mineral powder, 60 parts of fly ash, 16 parts of additive and 103 parts of water, wherein the coarse aggregate is common macadam and reinforced heavy slag, and the weight ratio of the common macadam to the reinforced heavy slag is 1.2: 1; the preparation method of the reinforced heavy slag comprises the following steps; additionally weighing common heavy slag, water, common Portland cement, fine sand and a water reducing agent according to the weight ratio of 1:0.2:1.1:0.8:0.02, wherein the mud content of the common heavy slag is not more than 1%; firstly, uniformly mixing water, common portland cement, fine sand and a water reducing agent to form dilute high-strength mortar, then pouring common heavy slag into the dilute high-strength mortar for stirring, after wrapping a layer of high-strength mortar, leaching and cooling until the high-strength mortar on the surface of the common heavy slag is hardened, and finally preparing the reinforced heavy slag with the gradation of 5-25 mm.

Performance test

The high-strength pervious concrete was prepared according to the methods in the examples and the respective proportions, and the following performance tests were carried out:

1. water permeability coefficient: detecting according to a testing method specified in CJJ/T135-2009 technical Specification for pervious cement concrete pavements;

2. compressive strength: testing according to GB/T500-81-2002 Standard of mechanical Properties test methods of ordinary concrete;

3. breaking strength: testing according to GB/T500-81-2002 Standard of mechanical Properties test methods of ordinary concrete;

4. heat resistance: the concrete slurry prepared in each embodiment and each proportion is prepared into a standard test block, then the standard test block is dried at 110 ℃ for 24h, then is placed in a high temperature furnace, is respectively burned at constant temperature of 400 ℃ for 3h, then is naturally cooled to room temperature, and the compressive strength of the burned test block is tested.

The test results are shown in table 2:

TABLE 2 results of performance test of concrete prepared in examples 1 to 23 and comparative examples 1 to 7

In examples 1 to 5, the water permeability coefficient of the concrete prepared by using the reinforcing agent prepared by mixing alumina, nano titanium dioxide and boron carbide is more than 3.2mm/s, the 28d compressive strength is more than 38.3MPa, and the flexural strength is up to 4.5MPa, which indicates that the concrete prepared by the method has better water permeability and higher compressive strength and flexural strength.

In examples 6 to 8, boron carbide and nano titanium dioxide were reduced by hot carbon, and then mixed with calcined alumina and hot pressed to prepare the reinforcing agent, and the water permeability coefficient of the high-strength pervious concrete prepared in examples 4 to 6 was improved compared with that of example 1, and the compressive strength and the flexural strength were significantly increased, which indicates that the reinforcing agent prepared by the method of the present application can increase the compressive strength and the flexural strength of the concrete.

In example 9, the reinforcing agent prepared in preparation example 4 is used, namely, the mixture of the product obtained by reducing boron carbide and nano titanium dioxide by hot carbon and alpha-alumina spherical particles is not subjected to hot pressing, compared with example 6, the compression strength and the breaking strength of concrete are reduced, and the hot pressing can increase the fracture toughness of the reinforcing agent and improve the hardness of the reinforcing agent.

In example 10, the reinforcing agent prepared in preparation example 5 using the reinforcing agent, i.e., without calcining alumina, was decreased in the surface porosity of alumina, and it was difficult to load a larger amount of TiB2 powder, thereby resulting in a decrease in the compressive strength and the flexural strength of concrete.

The data in Table 2 show that the concrete prepared in examples 11 to 12 has enhanced flexural strength by post-treating the α -alumina spherical particles with the silica sol in examples 11 to 12, and that the fracture toughness of the reinforcing agent can be improved by post-treating the α -alumina spherical particles with the silica sol.

Examples 13-15 compared to example 1, the results of testing the concrete prepared in examples 13-15 using the toughening fibers prepared in this application show that the compressive strength and flexural strength are increased, especially the flexural strength, significantly compared to example 1, and after a high temperature of 400 ℃ the compressive strength is greater than that of example 1 after a high temperature of 400 ℃, indicating that the heat resistance of the concrete prepared in examples 13-15 is improved.

In example 16, the toughening fibers prepared in preparation example 4 using the toughening fibers are not pretreated, and the data in table 2 show that the compressive strength of the concrete is reduced to some extent, and the breaking strength is obviously reduced, which indicates that the mechanical properties of the concrete can be improved by pretreating the ramie fibers.

In example 17, when the toughening fibers were prepared, the flexural strength of the concrete was significantly reduced and the heat resistance was reduced as shown by the data in table 2, without adding graphene.

In examples 18-19, the use of a binder, a water reducing agent, and an air entraining agent as additives, as shown by the data in Table 2, results in increased water permeability and increased flexural strength, indicating that the additives herein increase the water permeability of the concrete and prevent cracking of the concrete.

Compared with the concrete prepared in the example 18, the concrete prepared in the example 21 has the water permeability coefficient reduced but the compressive strength changed without adding the air-entraining agent in the example 21, which shows that the air-entraining agent can increase the water permeability of the concrete, and the compressive strength of the concrete does not change significantly under the action of the adhesive.

Example 22 compared with example 18, without adding adhesive, compared with example 18, the flexural strength and compressive strength of example 22 are reduced, which shows that the adhesive can increase the adhesive tightness of each component in the concrete and enhance the flexural strength and compressive strength.

Example 24 compared with example 1, in which not only the reinforcing agent and toughening fibers prepared in the present application but also alumina spherical particles in the reinforcing agent were post-treated and a mixture of a binder, an air-entraining agent and a water reducing agent was used as an admixture, example 23 was a most preferable example in which the water permeability coefficient was large, the compressive strength and the flexural strength were high, and the heat resistance was high, compared with examples 1, 6, 11, 13 and 18.

Compared with the example 1, the data in the table 2 shows that the flexural strength of the concrete prepared by the comparative example 1 is obviously reduced, and compared with the example 1, the data in the table 2 shows that the compressive strength of the concrete prepared by the comparative examples 2 to 4 is obviously reduced and the flexural strength is weakened, wherein the concrete prepared by the comparative examples 2 to 4 is not added with boron carbide, nano titanium dioxide and alumina respectively.

Comparative example 5 in order to use a commercially available reinforcing agent instead of the reinforcing agent in the present application, the concrete prepared in comparative example 5 was reduced in compressive strength and reduced in flexural strength as compared to example 1.

Comparative example 6 is high-strength pervious concrete in the prior art, the compressive strength of which reaches 37.3MPa, and the permeability coefficient of which reaches 4.4mm/s, but the concrete has small breaking strength, is easy to crack under external force, and has insufficient heat resistance.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The high-strength pervious concrete is characterized by comprising the following components in parts by weight: 240 parts of cement, 1300 parts of coarse aggregate, 1600 parts of mineral powder, 70-110 parts of fly ash, 8.5-25.2 parts of additive, 125 parts of water, 5-10 parts of toughening fiber and 10-20 parts of reinforcing agent;

the reinforcing agent comprises the following raw materials in parts by weight: 5-6 parts of alumina, 1-1.25 parts of nano titanium dioxide and 2-2.5 parts of boron carbide;

the preparation method of the reinforcing agent comprises the following steps: (1) drying boron carbide and nano titanium dioxide, then mixing with graphite powder, mixing for 1-2h at 1800 ℃ under 50-60Pa and 1700 plus materials in an inert atmosphere, and cooling to room temperature, wherein the mass ratio of the graphite powder to the nano titanium dioxide is 3.5-4: 1;

2. The high-strength pervious concrete according to claim 1, wherein the spherical particles of α -alumina in the alumina step (2) are post-treated by:

the alpha-alumina spherical particles are put into a silica sol water solution with the concentration of 20-35 percent and are uniformly mixed, and the mass ratio of the alpha-alumina spherical particles to the silica sol solution is 1: 0.3-0.4.

3. The high-strength pervious concrete according to claim 1, characterized in that the toughening fibers are prepared by the following method:

4. The high-strength pervious concrete of claim 3, wherein the mixing temperature in step (2) is 190-200 ℃, the mixing rotation speed is 20-25r/min, and the mixing time is 6-10 min.

5. The high-strength pervious concrete according to claim 1, characterized in that the admixture is made of an air-entraining agent, an adhesive and a water-reducing agent in a mass ratio of 1:0.4-0.8: 0.1-0.5.

6. The high-strength pervious concrete according to claim 5, characterized in that the binder is hydroxypropyl methylcellulose and polyethylene oxide in a mass ratio of 1: 1-1.5.

7. The high-strength pervious concrete according to claim 5, wherein the air entraining agent is prepared from polyacrylic acid and sodium dodecylbenzenesulfonate in a mass ratio of 2-3: 1.

8. The high-strength pervious concrete as claimed in claim 1, wherein the coarse aggregate comprises crushed stones and ceramsite in a mass ratio of 1:0.5-0.7, the crushed stones are continuous graded crushed stones with a particle size of 5-20mm, and the apparent density is 2650-³The bulk density is 1700-1750kg/m³The mud content is 0.3-0.5%, and the needle-shaped particle content is 6-8%; the ceramsite is coal gangue spherical ceramsite with 5-10mm particle size continuous gradation, and the bulk density of the ceramsite is 900-³The compact packing density is 980-1030kg/m³The apparent density is 1700-1800kg/m³。

9. The method for preparing high-strength pervious concrete according to any one of claims 1 to 8, characterized by comprising the steps of:

s1, weighing each component for later use;

s2, mixing the cement, the coarse aggregate, the mineral powder and the fly ash to prepare a dry mixture;