Recycled aggregate pervious concrete and preparation method thereof
阅读说明：本技术 一种再生骨料透水混凝土及其制备方法 (Recycled aggregate pervious concrete and preparation method thereof ) 是由 匡利君 井富磊 于 2021-08-02 设计创作，主要内容包括：本发明公开一种再生骨料透水混凝土及其制备方法,属于混凝土技术领域。本发明透水混凝土包括水泥、预处理再生骨料、矿渣微粉、粉煤灰、增韧改性聚丙烯纤维、可再分散性乳胶粉、硅烷偶联剂、羟丙基甲基纤维素、减水剂以及水为原料制备而成。本发明先进行壳聚糖预处理再生骨料,其次,将增韧改性聚丙烯纤维,使用纳米二氧化硅和十六烷基三甲基氯化铵进行改性提升纤维和再生骨料颗粒间的胶结力,整体上大幅提升材料强度。本发明原料配比科学,使用再生骨料制备透水混凝土,实现废弃资源的循环再利用,并且所得再生骨料透水混凝土的抗压强度高,透水性能好,抗冻性能好,对环境适应能力强,具有广泛的经济效益和社会效益。(The invention discloses recycled aggregate pervious concrete and a preparation method thereof, and belongs to the technical field of concrete. The pervious concrete is prepared from cement, pretreated recycled aggregate, slag micro powder, fly ash, toughened modified polypropylene fiber, redispersible latex powder, a silane coupling agent, hydroxypropyl methyl cellulose, a water reducing agent and water serving as raw materials. According to the invention, the regenerated aggregate is pretreated by chitosan, and then the toughened and modified polypropylene fiber is modified by using nano silicon dioxide and hexadecyl trimethyl ammonium chloride to improve the bonding force between the fiber and the regenerated aggregate, so that the strength of the material is greatly improved on the whole. The raw material proportion of the invention is scientific, the recycled aggregate is used for preparing the pervious concrete, the recycling of waste resources is realized, and the obtained recycled aggregate pervious concrete has high compressive strength, good water permeability, good frost resistance, strong environmental adaptability and wide economic and social benefits.)
1. The recycled aggregate pervious concrete is characterized by being prepared from the following raw materials in parts by weight: 100-150 parts of cement, 400-600 parts of pretreated recycled aggregate, 50-80 parts of slag micro powder, 30-50 parts of fly ash, 10-20 parts of toughened modified polypropylene fiber, 5-15 parts of redispersible latex powder, 3-8 parts of silane coupling agent, 3-7 parts of hydroxypropyl methyl cellulose, 3-5 parts of water reducing agent and 30-80 parts of water.
2. The recycled aggregate pervious concrete of claim 1, wherein the preparation method of the pretreated recycled aggregate is as follows: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding 30% ethanol solution according to the solid-liquid ratio of 1g:100ml, continuously stirring for 1-3h, and drying to obtain the pretreated recycled aggregate.
3. The recycled aggregate porous concrete as claimed in claim 1, wherein the specific surface area of the slag micropowder is 200-350m2/kg。
4. The recycled aggregate pervious concrete of claim 1, wherein the preparation method of the toughening modified polypropylene fiber comprises the following steps: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1-2h, adding hexadecyl trimethyl ammonium chloride with the mass concentration of 30% of the mixed solution, heating to 80-85 ℃, reacting for 90-120 min, carrying out suction filtration, washing a filter cake with distilled water with the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at 80 ℃ to obtain the toughened modified polypropylene fibers.
5. The recycled aggregate pervious concrete of claim 1, wherein the silane coupling agent is 3-isocyanatopropyltriethoxysilane.
6. The recycled aggregate pervious concrete of claim 1, characterized in that the water reducing agent is a polycarboxylic acid water reducing agent.
7. The preparation method of the recycled aggregate pervious concrete of any one of claims 1 to 6, characterized by comprising the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparation of pretreated recycled aggregate: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding an ethanol solution with the mass concentration of 30% according to the solid-liquid ratio of 1g:100ml, continuously stirring for 1-3h, and drying to obtain the pretreated recycled aggregate;
(3) preparing toughened modified polypropylene fibers: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1-2h, adding hexadecyl trimethyl ammonium chloride with the mass concentration of 30% of the mixed solution, heating to 80-85 ℃, reacting for 90-120 min, carrying out suction filtration, washing a filter cake with distilled water with the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at 80 ℃ to obtain toughened modified polypropylene fibers;
(4) adding 3-8 parts of silane coupling agent, 3-7 parts of hydroxypropyl methyl cellulose, 3-5 parts of water reducing agent and 30-80 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(5) and then adding 150 parts of cement, 400 parts of pretreated recycled aggregate, 50-80 parts of slag micro powder, 30-50 parts of fly ash, 10-20 parts of toughened modified polypropylene fiber and 5-15 parts of redispersible latex powder into the mixture A, and stirring for 1-2h to obtain the recycled aggregate permeable concrete.
Technical Field
The invention belongs to the technical field of concrete, and particularly relates to recycled aggregate pervious concrete and a preparation method thereof.
Background
The regenerated pervious concrete is light porous concrete prepared by uniformly mixing cement, aggregate, an additive and water. The preparation of the recycled aggregate pervious concrete is based on the theory of preparing the pervious concrete part, the recycled aggregate is selected for the aggregate part or completely replaces the recycled aggregate, and the compressive strength and the water permeability of the recycled aggregate pervious concrete are exerted in a balanced manner through a reasonable mixing proportion. The recycled aggregate pretreatment refers to that the building waste concrete, mortar, stone, tiles and the like are crushed, cleaned and graded, and then are matched with gradation according to a certain proportion, and the pervious concrete is prepared by mixing part or all of the recycled aggregate. The surface of the coarse aggregate in the recycled pervious concrete is coated with a thin layer of cement slurry to be bonded with each other, so that a honeycomb structure with uniformly distributed internal pores is formed, and the recycled pervious concrete has the characteristics of balanced compressive strength, water permeability, energy conservation and environmental protection.
The pervious concrete prepared by the recycled aggregate can improve the utilization rate of construction waste and promote the resource utilization of solid waste on the one hand, and on the other hand, the pervious concrete can be applied to urban roads and squares, can reduce rainwater into underground water, reduce the urban drainage pressure, solve urban waterlogging, improve the urban ecological environment, improve the urban livable level, and if the recycled aggregate is adopted in a sponge city, the environmental protection performance of the city can be greatly improved.
At present, the strength of the recycled aggregate pervious concrete in the prior art is usually lower, which is mainly because the high-strength concrete proportioning is adopted in the preparation of the pervious concrete, and because the toughness is not enough, the strong brittleness is easily generated, especially the defect of the large aggregate recycled concrete is more obvious, and the salt corrosion resistance is poor, so the durability is not good. Many companies have therefore added various additives to pervious concrete to improve its strength properties. However, the raw materials are expensive, the process steps are complicated, the manufacturing cost of the recycled aggregate pervious concrete is greatly increased to a certain extent, the waste recycling of the recycled aggregate is hindered, the obtained pervious concrete has low permeability coefficient and general strength, and the permeability coefficient and the strength cannot be considered simultaneously.
Disclosure of Invention
The invention provides a recycled aggregate pervious concrete and a preparation method thereof.
In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:
the recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 100-150 parts of cement, 400-600 parts of pretreated recycled aggregate, 50-80 parts of slag micro powder, 30-50 parts of fly ash, 10-20 parts of toughened modified polypropylene fiber, 5-15 parts of redispersible latex powder, 3-8 parts of silane coupling agent, 3-7 parts of hydroxypropyl methyl cellulose, 3-5 parts of water reducing agent and 30-80 parts of water.
Further, the recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 150 parts of cement, 600 parts of pretreated recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of toughened and modified polypropylene fiber, 15 parts of redispersible latex powder, 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water.
Further, the preparation method of the pretreated recycled aggregate comprises the following steps: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding 30% ethanol solution according to the solid-liquid ratio of 1g:100ml, continuously stirring for 1-3h, and drying to obtain the pretreated recycled aggregate.
Further, the specific surface area of the slag micro powder is 200-350m2/kg。
Further, the preparation method of the toughened and modified polypropylene fiber comprises the following steps: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1-2h, adding hexadecyl trimethyl ammonium chloride with the mass concentration of 30% of the mixed solution, heating to 80-85 ℃, reacting for 90-120 min, carrying out suction filtration, washing a filter cake with distilled water with the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at 80 ℃ to obtain the toughened modified polypropylene fibers.
The polypropylene fiber of the invention adopts commercial polypropylene fiber, the length is 6mm-15mm, and the equivalent diameter is 0.6 mm.
Further, the silane coupling agent is 3-isocyanatopropyl triethoxysilane.
Further, the water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparation of pretreated recycled aggregate: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding an ethanol solution with the mass concentration of 30% according to the solid-liquid ratio of 1g:100ml, continuously stirring for 1-3h, and drying to obtain the pretreated recycled aggregate;
(3) preparing toughened modified polypropylene fibers: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1-2h, adding hexadecyl trimethyl ammonium chloride with the mass concentration of 30% of the mixed solution, heating to 80-85 ℃, reacting for 90-120 min, carrying out suction filtration, washing a filter cake with distilled water with the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at 80 ℃ to obtain toughened modified polypropylene fibers;
(4) adding 3-8 parts of silane coupling agent, 3-7 parts of hydroxypropyl methyl cellulose, 3-5 parts of water reducing agent and 30-80 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(5) and then adding 150 parts of cement, 400 parts of pretreated recycled aggregate, 50-80 parts of slag micro powder, 30-50 parts of fly ash, 10-20 parts of toughened modified polypropylene fiber and 5-15 parts of redispersible latex powder into the mixture A, and stirring for 1-2h to obtain the recycled aggregate permeable concrete.
Advantageous effects
(1) The invention does not directly use the recycled aggregate to prepare the pervious concrete, but uses the pervious concrete after the chitosan pretreatment. The chitosan is an environment-friendly natural chain organic high molecular polymer and also has the function of toughening and modifying the inorganic cementing material. The chitosan and the sodium oleate have good film forming and penetrating effects, and can effectively promote the chitosan and the sodium oleate on the surface and the gaps of the recycled aggregate under the action of alkaliRapid film formation and penetration. The chitosan molecular skeleton contains a large amount of-NH2and-OH functional groups, on one hand, the modified polypropylene fiber has stronger adsorbability, can effectively adsorb subsequent modified polypropylene fibers, and on the other hand, the modified polypropylene fiber can generate chelation with most heavy metal ions, so that the problem of environmental pollution hidden by recycled aggregate with a complex source is solved.
(2) And secondly, a small amount of nano silicon dioxide is added into the polypropylene fiber, the polypropylene fiber can improve the brittleness and the ductility of the material, hexadecyl trimethyl ammonium chloride is used for modification, and the hexadecyl trimethyl ammonium chloride has a strong polar group, so that the nano silicon dioxide is effectively fixed, the calcium silicate hydrate C-S-H can be effectively adsorbed, the cementing power between the polypropylene fiber and other particles, particularly between regenerated aggregate particles, is improved, and the strength of the material is greatly improved on the whole.
(3) The raw material proportion of the invention is scientific, the recycled aggregate is used for preparing the pervious concrete, the recycling of waste resources is realized, and the obtained recycled aggregate pervious concrete has high compressive strength, good water permeability, good frost resistance, strong environmental adaptability and wide economic and social benefits.
Detailed Description
The technical solution of the present invention is further described below with reference to specific embodiments, but is not limited thereto.
Example 1
The recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 100 parts of cement, 400 parts of pretreated recycled aggregate, 50 parts of slag micropowder, 30 parts of fly ash, 10 parts of toughened and modified polypropylene fiber, 5 parts of redispersible latex powder, 3 parts of silane coupling agent, 3 parts of hydroxypropyl methyl cellulose, 3 parts of water reducing agent and 30 parts of water.
The preparation method of the pretreated recycled aggregate comprises the following steps: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding 30% ethanol solution according to the solid-liquid ratio of 1g:100ml, continuously stirring for 1h, and drying to obtain the pretreated recycled aggregate.
The specific surface area of the slag micro powder is 200-350m2/kg。
The preparation method of the toughened and modified polypropylene fiber comprises the following steps: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1h, adding hexadecyl trimethyl ammonium chloride with the mass of 30% of the mixed solution, heating to 80 ℃, reacting for 90min, carrying out suction filtration, washing a filter cake with distilled water at the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at the temperature of 80 ℃ to obtain the toughened and modified polypropylene fibers.
The polypropylene fibers of this example were commercially available polypropylene fibers having a length of 6mm to 15mm and an equivalent diameter of 0.6 mm.
The silane coupling agent is 3-isocyanatopropyl triethoxysilane.
The water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparation of pretreated recycled aggregate: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding an ethanol solution with the mass concentration of 30% according to the solid-liquid ratio of 1g:100ml, continuously stirring for 1h, and drying to obtain the pretreated recycled aggregate;
(3) preparing toughened modified polypropylene fibers: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1h, adding hexadecyl trimethyl ammonium chloride with the mass of 30% of the mixed solution, heating to 80 ℃, reacting for 90min, carrying out suction filtration, washing a filter cake with distilled water at 60 ℃ which is 5 times that of the filter cake, and then placing the filter cake in an oven for drying at 80 ℃ to obtain toughened and modified polypropylene fibers;
(4) adding 3 parts of silane coupling agent, 3 parts of hydroxypropyl methyl cellulose, 3 parts of water reducing agent and 30 parts of water into a stirrer according to the parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(5) and then adding 100 parts of cement, 400 parts of pretreated recycled aggregate, 50 parts of slag micro powder, 30 parts of fly ash, 10 parts of toughened modified polypropylene fiber and 5 parts of redispersible latex powder into the mixture A, and stirring for 1h to obtain the recycled aggregate permeable concrete.
The raw materials of the permeable concrete pavement brick are doped with polypropylene fibers, so that the compressive strength and the splitting tensile strength of the brick can be improved, and the permeability coefficient of the fiber doped with nano-silica is increased, so that the water permeability of the brick is improved.
Example 2
The recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 120 parts of cement, 500 parts of pretreated recycled aggregate, 70 parts of slag micropowder, 40 parts of fly ash, 15 parts of toughened and modified polypropylene fiber, 10 parts of redispersible latex powder, 5 parts of silane coupling agent, 5 parts of hydroxypropyl methyl cellulose, 4 parts of water reducing agent and 50 parts of water.
The preparation method of the pretreated recycled aggregate comprises the following steps: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding 30% ethanol solution according to the solid-liquid ratio of 1g:100ml, continuously stirring for 3h, and drying to obtain the pretreated recycled aggregate.
The specific surface area of the slag micro powder is 200-350m2/kg。
The preparation method of the toughened and modified polypropylene fiber comprises the following steps: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 2 hours, adding hexadecyl trimethyl ammonium chloride with the mass of 30% of the mixed solution, heating to 85 ℃, reacting for 120min, carrying out suction filtration, washing a filter cake with distilled water at 60 ℃ which is 5 times that of the filter cake, and then placing the filter cake in an oven for drying at 80 ℃ to obtain the toughened and modified polypropylene fibers.
The polypropylene fibers of this example were commercially available polypropylene fibers having a length of 6mm to 15mm and an equivalent diameter of 0.6 mm.
The silane coupling agent is 3-isocyanatopropyl triethoxysilane.
The water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparation of pretreated recycled aggregate: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding an ethanol solution with the mass concentration of 30% according to the solid-liquid ratio of 1g:100ml, continuously stirring for 3h, and drying to obtain the pretreated recycled aggregate;
(3) preparing toughened modified polypropylene fibers: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 2 hours, adding hexadecyl trimethyl ammonium chloride with the mass of 30% of the mixed solution, heating to 85 ℃, reacting for 120min, carrying out suction filtration, washing a filter cake with distilled water at the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at the temperature of 80 ℃ to obtain toughened and modified polypropylene fibers;
(4) adding 5 parts of silane coupling agent, 5 parts of hydroxypropyl methyl cellulose, 4 parts of water reducing agent and 50 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(5) and then adding 120 parts of cement, 500 parts of pretreated recycled aggregate, 70 parts of slag micro powder, 40 parts of fly ash, 15 parts of toughened modified polypropylene fiber and 10 parts of redispersible latex powder into the mixture A, and stirring for 2 hours to obtain the recycled aggregate permeable concrete.
The fly ash can improve the compression resistance of the recycled aggregate pervious concrete, but can reduce the water permeability of the recycled aggregate pervious concrete. The fiber can obviously improve the water permeability. The compressive strength of the recycled aggregate permeable concrete can be obviously improved by the fibers with a certain mixing amount, and if the compressive strength exceeds a certain value, the compressive strength is gradually reduced.
Example 3
The recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 150 parts of cement, 600 parts of pretreated recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of toughened and modified polypropylene fiber, 15 parts of redispersible latex powder, 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water.
The preparation method of the pretreated recycled aggregate comprises the following steps: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding 30% ethanol solution according to the solid-liquid ratio of 1g:100ml, continuously stirring for 3h, and drying to obtain the pretreated recycled aggregate.
The specific surface area of the slag micro powder is 200-350m2/kg。
The preparation method of the toughened and modified polypropylene fiber comprises the following steps: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1-2 hours, adding hexadecyl trimethyl ammonium chloride with the mass concentration of 30% of the mixed solution, heating to 85 ℃, reacting for 120min, carrying out suction filtration, washing a filter cake with distilled water with the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at 80 ℃ to obtain the toughened and modified polypropylene fibers.
The polypropylene fibers of this example were commercially available polypropylene fibers having a length of 6mm to 15mm and an equivalent diameter of 0.6 mm.
The silane coupling agent is 3-isocyanatopropyl triethoxysilane.
The water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparation of pretreated recycled aggregate: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding an ethanol solution with the mass concentration of 30% according to the solid-liquid ratio of 1g:100ml, continuously stirring for 3h, and drying to obtain the pretreated recycled aggregate;
(3) preparing toughened modified polypropylene fibers: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 2 hours, adding hexadecyl trimethyl ammonium chloride with the mass of 30% of the mixed solution, heating to 85 ℃, reacting for 120min, carrying out suction filtration, washing a filter cake with distilled water at the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at the temperature of 80 ℃ to obtain toughened and modified polypropylene fibers;
(4) adding 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(5) and then adding 150 parts of cement, 600 parts of pretreated recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of toughened modified polypropylene fiber and 15 parts of redispersible latex powder into the mixture A, and stirring for 2 hours to obtain the recycled aggregate permeable concrete.
Comparative example 1
The recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 150 parts of cement, 600 parts of recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of toughened and modified polypropylene fiber, 15 parts of redispersible latex powder, 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water.
The specific surface area of the slag micro powder is 200-350m2/kg。
The preparation method of the toughened and modified polypropylene fiber comprises the following steps: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 1-2 hours, adding hexadecyl trimethyl ammonium chloride with the mass concentration of 30% of the mixed solution, heating to 85 ℃, reacting for 120min, carrying out suction filtration, washing a filter cake with distilled water with the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at 80 ℃ to obtain the toughened and modified polypropylene fibers.
The polypropylene fiber of the comparative example is a commercial polypropylene fiber with a length of 6mm-15mm and an equivalent diameter of 0.6 mm.
The silane coupling agent is 3-isocyanatopropyl triethoxysilane.
The water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparing toughened modified polypropylene fibers: uniformly dispersing polypropylene fibers and nano silicon dioxide in an oxalic acid solution with the mass concentration of 30% according to the mass ratio of 1:0.5, magnetically stirring for 2 hours, adding hexadecyl trimethyl ammonium chloride with the mass of 30% of the mixed solution, heating to 85 ℃, reacting for 120min, carrying out suction filtration, washing a filter cake with distilled water at the temperature of 5 times 60 ℃, and then placing the filter cake in an oven for drying at the temperature of 80 ℃ to obtain toughened and modified polypropylene fibers;
(3) adding 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(4) and then adding 150 parts of cement, 600 parts of recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of toughened and modified polypropylene fiber and 15 parts of redispersible latex powder into the mixture A, and stirring for 2 hours to obtain the recycled aggregate permeable concrete.
This comparative example is the same as example 3 except that the pretreatment of the recycled aggregate was not carried out.
Comparative example 2
The recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 150 parts of cement, 600 parts of pretreated recycled aggregate, 80 parts of slag micropowder, 50 parts of fly ash, 20 parts of polypropylene fiber, 15 parts of redispersible latex powder, 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water.
The preparation method of the pretreated recycled aggregate comprises the following steps: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding 30% ethanol solution according to the solid-liquid ratio of 1g:100ml, continuously stirring for 3h, and drying to obtain the pretreated recycled aggregate.
The specific surface area of the slag micro powder is 200-350m2/kg。
The polypropylene fiber of the comparative example is a commercial polypropylene fiber with a length of 6mm-15mm and an equivalent diameter of 0.6 mm.
The silane coupling agent is 3-isocyanatopropyl triethoxysilane.
The water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) preparation of pretreated recycled aggregate: adding the recycled aggregate particles, chitosan, sodium oleate and sodium hydroxide into a uniform stirrer according to the mass ratio of 10:1:1:0.5, uniformly stirring, adding an ethanol solution with the mass concentration of 30% according to the solid-liquid ratio of 1g:100ml, continuously stirring for 3h, and drying to obtain the pretreated recycled aggregate;
(3) adding 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(4) and then adding 150 parts of cement, 600 parts of pretreated recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of polypropylene fiber and 15 parts of redispersible latex powder into the mixture A, and stirring for 2 hours to obtain the recycled aggregate permeable concrete.
This comparative example is the same as example 3 except that the toughening modification of the polypropylene fiber is not performed.
Comparative example 3
The recycled aggregate pervious concrete is prepared from the following raw materials in parts by weight: 150 parts of cement, 600 parts of recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of polypropylene fiber, 15 parts of redispersible latex powder, 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water.
The specific surface area of the slag micro powder is 200-350m2/kg。
The polypropylene fiber of the comparative example is a commercial polypropylene fiber with a length of 6mm-15mm and an equivalent diameter of 0.6 mm.
The silane coupling agent is 3-isocyanatopropyl triethoxysilane.
The water reducing agent is a polycarboxylic acid water reducing agent.
A preparation method of recycled aggregate pervious concrete comprises the following steps:
(1) crushing, screening, washing and drying the waste concrete to prepare recycled aggregate, wherein the particle size of the recycled aggregate is 10-20 mm;
(2) adding 8 parts of silane coupling agent, 7 parts of hydroxypropyl methyl cellulose, 5 parts of water reducing agent and 80 parts of water into a stirrer according to parts by weight, and stirring and mixing uniformly to obtain a mixture A;
(3) and then adding 150 parts of cement, 600 parts of recycled aggregate, 80 parts of slag micro powder, 50 parts of fly ash, 20 parts of polypropylene fiber and 15 parts of redispersible latex powder into the mixture A, and stirring for 2 hours to obtain the recycled aggregate permeable concrete.
The comparative example is the same as example 3 except that the recycled aggregate is not pretreated and the polypropylene fiber is toughened and modified.
Performance testing
Test method
The main performance indexes of the pervious concrete are strength and permeability, the strength is represented by compressive strength and cleavage resistance, and the permeability is represented by porosity.
The test method is as follows:
compressive strength: the test is carried out according to the regulations in GB/T50081-2019 ordinary concrete mechanical property test method. The test block size is 150mm multiplied by 150mm, 3 identical test blocks are prepared in each group, maintenance is carried out for 7d or 28d according to requirements, and the measurement results are averaged.
Indexes such as water permeability coefficient, volume water absorption and porosity: the test was carried out according to the regulations in standard CJJ/T135-2009 technical Specification for Water-permeable Cement concrete pavements.
And (3) determining the compressive strength loss rate after freeze-thaw cycling according to the test method standard of the long-term performance and the durability of the GB/T50082-2009 common concrete.
The results of the experiment are shown in table 1:
table 1 results of performance testing
On the premise of ensuring higher water permeability coefficient, the 28-day compressive strength of the material is greatly improved, the use requirements of the water permeable concrete in various fields are completely met, and the recycling and reutilization of the recycled concrete are practically realized. Compared with the prior art, the performance of the composite material is obviously reduced in the comparative example 1 without pretreatment and the comparative example 2 without toughening modification, the pretreated recycled aggregate and the toughened modified polypropylene fiber have a synergistic effect on the improvement of the strength and the water permeability of the material, and the pretreated recycled aggregate and the toughened modified polypropylene fiber are weak in one case and jointly realize the overall improvement of the comprehensive performance of the material.
It should be noted that the above-mentioned embodiments are only some of the preferred modes for implementing the invention, and not all of them. Obviously, all other embodiments obtained by persons of ordinary skill in the art based on the above-mentioned embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.