CN113773029A

CN113773029A - Concrete capable of recycling waste and preparation process thereof

Info

Publication number: CN113773029A
Application number: CN202111093825.9A
Authority: CN
Inventors: 明勇; 陈勇; 余勇
Original assignee: Sichuan Hengding Building Materials Co ltd
Current assignee: Sichuan Hengding Building Materials Co ltd
Priority date: 2021-09-17
Filing date: 2021-09-17
Publication date: 2021-12-10

Abstract

The application relates to the field of building materials, and particularly discloses waste recycling concrete and a preparation process thereof. The concrete for recycling the waste comprises the following components in parts by weight: 300 portions of cement-; the preparation method comprises the following steps: uniformly mixing cement, sand, broken stone and waste materials to prepare a premix; and mixing the expanded and vitrified small balls, the EPS particles, the additive and water, adding the premix, and uniformly mixing to obtain the waste recycled concrete. The waste recycled concrete has the advantages of high porosity, good water permeability and strong freeze-thaw resistance.

Description

Concrete capable of recycling waste and preparation process thereof

Technical Field

The application relates to the technical field of building materials, in particular to waste recycling concrete and a preparation process thereof.

Background

Along with the progress of urban construction, the earth's surface of modern city is covered gradually by impervious road surfaces such as pitch, concrete, masonry, these road surfaces have prevented the infiltration of rainwater, when meetting heavy rain or torrential rain, the rainwater collects on the road surface, leads to road surface ponding on a large scale, still can accelerate urban heat island effect's formation in addition, influences urban environment's comfort level. The pervious concrete has certain water permeability, rainwater can permeate underground to supplement underground water through the pervious concrete, the water permeability and air permeability of the pervious concrete are very close to the characteristics of soil, and when the temperature is very high, the underground water can be evaporated to the atmosphere through the pervious bricks, so that the ecological environment of a city is improved.

In the development process of the building industry, a large amount of building wastes are generated by a large amount of demolition projects, nearly 2 hundred million tons of building wastes are generated in China every year and are generally directly treated in an open-air stacking or landfill mode, and organic acids, heavy metal ions and the like volatilized by the building wastes cause great harm to the surrounding environment and have lasting influence on the ecological environment. On the other hand, in the sponge city construction process, a large amount of concrete with water permeability and water retention performance needs to be used, so that the construction waste is used in the pervious concrete, and the problem of preparing the concrete with good water permeability is urgently needed to be solved.

Disclosure of Invention

In order to realize the recycling of construction waste and obtain concrete with good water permeability and water retention, the application provides the concrete with recycled waste and a preparation process thereof.

In a first aspect, the present application provides a concrete for recycling waste, which adopts the following technical scheme:

the waste recycling concrete comprises the following components in parts by weight: 300 portions of cement-;

the waste material is made by the following method:

(1) crushing, grinding and sieving construction waste to prepare waste micro powder, soaking the waste micro powder in a mixed solution prepared from diethylenetriamine pentamethylenephosphonic acid and polyisobutylene succinimide, filtering, drying the waste micro powder, calcining for 3-4h at the temperature of 1000-1100 ℃, and cooling, wherein the mass ratio of the diethylenetriamine pentamethylenephosphonic acid to the polyisobutylene succinimide is 1: 0.4-0.8;

(2) air drying and crushing the straws, soaking the straws in polyacrylamide aqueous solution with the mass percentage concentration of 0.07-0.1%, adding waste micro powder, uniformly mixing, drying and grinding to prepare a waste material, wherein the mass ratio of the straws to the waste micro powder is 0.1-0.3: 1.

By adopting the technical scheme, the concrete is prepared by adopting the components such as the expanded and vitrified micro-beads, the EPS particles, the waste materials and the like, so that the utilization of the construction waste can relieve a series of environmental and social problems caused by the construction waste on one hand, and on the other hand, the construction waste replaces natural raw materials, thereby reducing the consumption of natural resources in the construction industry, protecting the environment which human beings rely on for survival and providing guarantee and support for the sustainable development of society and economy.

The expanded and vitrified micro bubbles have high water absorption rate, the surface of EPS particles is not hydrophilic, water can quickly slide off from the surface of the EPS particles, and the water can quickly enter the concrete and quickly pass through and run off from the inside; the construction waste is crushed and screened to remove large particles, gravel impurities and the like, but the construction waste also contains a certain amount of unhydrated clinker particles, the outer layers of the unhydrated particles are wrapped by hydration products, after the construction waste is crushed, the hydration products on the surface layer are exposed by glass, the unhydrated particles are exposed, and the diethylenetriamine pentamethylenephosphonic acid has a chelating effect on metal ions such as calcium ions, magnesium ions and the like, so that the concentration of the metal ions in the construction waste can be effectively reduced, the dissolution of more metal ions is facilitated, the gelling reaction activity of the construction waste is promoted, then, after high-temperature calcination, minerals such as C3S and the like in the unhydrated clinker particles play a role of crystal seeds, the formation of the minerals in cement is facilitated, and the compressive strength of the concrete is improved.

After the polyacrylamide solution is soaked in the straw, the polyacrylamide can generate same tiny charges and is loaded on the outer wall of the straw, so that the straw generates mutual repulsion force of the same charges, the mixing uniformity of the straw and the waste micro powder is improved, the bonding capability of the interface of the straw soaked in the polyacrylamide solution is enhanced, the waste micro powder can be uniformly coated on the surface, the porosity of the waste micro powder surface is increased by the straw, and the water permeability of concrete is enhanced.

Preferably, the straw is pretreated by the following steps: soaking the straws in a sodium hydroxide solution for 8-16h, drying, then placing the dried straws in a mixed solution prepared from 0.3-0.5 part by weight of melamine formaldehyde resin, 0.04-0.08 part by weight of nano titanium dioxide and 0.8-1 part by weight of ethanol, vacuum-soaking, drying, and then uniformly spraying a sodium silicate solution with the mass percentage concentration of 1-2% on the surfaces of the straws, wherein the spraying amount of the sodium silicate solution is 10-20% of the mass of the straws.

By adopting the technical scheme, the straws are easy to rot in the concrete due to acid-base corrosion or oxidation, the mechanical properties of the concrete and the reinforcing steel bars in the concrete are affected, and the service life of the concrete is shortened; soaking the straws in a sodium hydroxide solution to remove lignin and other impurities in the straws, so that the surfaces of the straws are uneven, and surface holes are enlarged, and the combination of the straws with melamine formaldehyde resin and nano titanium dioxide is facilitated, the melamine formaldehyde resin and the nano titanium dioxide can be attached to the surfaces of the straws and enter the pores of the straws under the vacuum action, so that the tensile strength of the straws is enhanced, the nano titanium dioxide can enhance the hydrophobicity of the melamine formaldehyde resin, and the moisture is not easy to stay in the concrete, so that the moisture remained in the concrete is prevented, the concrete is prevented from cracking due to low-temperature crystal expansion, and the freeze-thaw resistance of the concrete is improved; the melamine formaldehyde resin and the nano titanium dioxide entering the straw can further improve the corrosion resistance of the straw, and the silicic acid solution has strong corrosion resistance and adhesion, can improve the corrosion resistance of the straw, improves the interface bonding force between the straw and waste micro powder, and improves the mechanical property of concrete.

Preferably, the vitrified micro bubbles are pretreated by the following steps:

(1) soaking waste rubber powder in a phenol-formaldehyde linear resin acetone solution, wherein the mass ratio of the waste rubber powder to the phenol-formaldehyde linear resin is 1:0.3-0.5, and drying under reduced pressure;

(2) uniformly mixing 1-2 parts by weight of silane coupling agent, 0.03-0.05 part by weight of hexamethylenetetramine and 0.8-1 part by weight of water to prepare spraying liquid, adding the waste rubber powder prepared in the step (1), uniformly spraying the mixture on the expanded and vitrified micro bubbles after uniform mixing, heating to 150 ℃ and keeping the temperature for 10-15min, cooling, and controlling the mass ratio of the expanded and vitrified micro bubbles, the waste rubber powder and the spraying liquid to be 1:0.2-0.4: 0.1-0.3.

By adopting the technical scheme, after the waste rubber powder is soaked in acetone solution of linear phenolic resin, the acetone is removed by drying under reduced pressure, the linear phenolic resin is coated on the surface of the waste rubber powder, the linear phenolic resin has the effects of reinforcement and hydrophobicity, then the waste rubber powder coated with the linear phenolic resin, a silane coupling agent, hexamethylenetetramine and the like are sprayed on the surface of the expanded and vitrified micro bubbles, under the high-temperature heating, the linear phenolic resin is cured under the action of the hexamethylenetetramine, so that a connecting film is formed between the expanded and vitrified micro bubbles and the waste rubber powder, the waste rubber powder which is sprayed and adhered on the surface of the expanded and vitrified micro bubbles can seal surface defects of the expanded and vitrified micro bubbles caused by various reasons, thereby preventing the expanded and vitrified micro bubbles from absorbing and storing water, and ensuring that the water quickly flows from the surface of the expanded and vitrified micro bubbles without remaining in concrete after absorbing the water, therefore, the freeze-thaw resistance effect is improved, in addition, the waste rubber particles on the surfaces of the expanded and vitrified micro bubbles have elasticity, the expansion stress generated by low-temperature condensation of water can be relieved, and the freeze resistance effect is improved.

Preferably, the particle size of the expanded and vitrified micro bubbles is 30-50 meshes, the particle size of the waste rubber powder is 100-150nm, and the silane coupling agent is KH-560.

By adopting the technical scheme, the particle size of the expanded and vitrified micro bubbles is large, the particle size of the waste rubber powder is in a nanometer level, the waste rubber powder is convenient to adhere to the surface of the expanded and vitrified micro bubbles, the KH-560 can be connected with the linear phenolic resin, the compatibility of the linear phenolic resin and the expanded and vitrified micro bubbles is increased, and the adhesive force between the waste rubber powder and the expanded and vitrified micro bubbles is improved.

Preferably, the EPS particles are pretreated by: mixing EPS particles, polyvinyl alcohol, sulphoaluminate cement and water according to the mass ratio of 1:0.3-0.5:2-3:1-1.5, and drying.

By adopting the technical scheme, the EPS particles are light in weight and are easy to float upwards when being stirred with concrete slurry, so that the EPS particles are mixed with polyvinyl alcohol and aluminum sulfate cement, under the adhesion action of the polyvinyl alcohol, the sulphoaluminate cement is coated on the surfaces of the EPS particles, the dead weight of the EPS particles is increased, and the EPS particles are prevented from floating upwards, in addition, the sulphoaluminate cement mainly comprises anhydrous calcium sulphoaluminate and beta-type dicalcium silicate, has the advantages of negative temperature hardening and low alkalinity, and has the liquid phase alkalinity of 10.5-11.5, so that the corrosion effect of the alkalinity action of the concrete on straws can be reduced.

Preferably, the waste material is composed of waste material with the particle size of 0.15-3mm and waste material with the particle size of 5-10mm, and the mass ratio of the waste material with the particle size of 0.15-3mm to the waste material with the particle size of 5-10mm is 1-1.5: 3.7-4.2.

By adopting the technical scheme, the waste materials with different understanding ranges form permeable pores in concrete, the utilization rate of the construction waste is improved, and secondary byproducts are not generated.

Preferably, the additive comprises a high-efficiency water reducing agent, an organosilicon water repellent and silica fume, and the mass ratio of the high-efficiency water reducing agent to the organosilicon water repellent to the silica fume is 0.1-0.3:2-5: 10-20.

By adopting the technical scheme, the organic silicon water repellent can increase the hydrophobicity of the cementing material, so that moisture can be quickly seeped out of the concrete, and the frost resistance of the concrete in a severe cold area is improved; the high-efficiency water reducing agent and the silica fume can enhance the compressive strength of the concrete.

Preferably, the crushed stone is 5-20mm continuous graded crushed stone, the crushing index is less than or equal to 6 percent, the mud content is less than 0.5 percent, and the mud block content is less than 0.1 percent.

Through adopting above-mentioned technical scheme, the graded rubble of different particle diameters can form mutual lapped skeleton texture, and the less garrulous stone of particle diameter can fill in the hole that the great rubble of particle diameter contacted each other and formed, forms the skeleton, and the granule of mechanism sand is little, can fill in the skeleton that coarse aggregate formed, improves the closely knit degree and the intensity of concrete, reduces the porosity of concrete, improves the compressive strength of concrete.

Preferably, the sand is machine-made sand with the particle size of 800-1000 meshes and the apparent density of 1800-2000Kg/cm³。

By adopting the technical scheme, when the particle size is larger, the coarse particles are more, the grading is unreasonable, the workability is poor, the particle size is smaller, the fine powder is more, the water demand is increased, and the concrete strength is reduced.

In a second aspect, the present application provides a preparation process of concrete with recycled waste, which adopts the following technical scheme:

a preparation process of waste recycled concrete comprises the following steps:

uniformly mixing cement, sand, broken stone and waste materials to prepare a premix;

and mixing the expanded and vitrified small balls, the EPS particles, the additive and water, adding the premix, and uniformly mixing to obtain the waste recycled concrete.

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

1. because this application adopts components such as expanded and vitrified micro bubbles, EPS granule and building waste to prepare pervious concrete, recycles building waste, improves its economic value, reduces its influence to the environment, uses the straw to mix with building waste in addition, mixes in the concrete, can improve the water permeability of concrete, improves the effect of permeating water.

2. Preferentially adopt components such as sodium hydroxide solution, melamine formaldehyde resin, nanometer titanium dioxide to carry out the preliminary treatment to the straw in this application, through the vacuum impregnation effect, inside melamine formaldehyde resin and nanometer titanium dioxide can fully get into the straw, improve the tensile strength of straw to improve the corrosion resisting property of straw, improve the hydrophobicity of straw simultaneously, prevent that moisture from in its inside storage, cause the concrete to split at low temperature, improve the frost resisting effect of concrete.

3. The waste rubber powder is preferably pretreated by adopting the linear phenolic resin, then is mixed with the silane coupling agent, the hexamethylenetetramine and the like, and is sprayed on the surface of the expanded and vitrified micro-bead, after the linear phenolic resin is heated, the linear phenolic resin is melted, the waste rubber powder and the expanded and vitrified micro-bead are bonded, the expansion stress of water when the water is frozen at a low temperature can be relieved by the waste rubber powder coated on the surface of the expanded and vitrified micro-bead, the frost resistance of concrete is improved, meanwhile, the hydrophobicity of the waste rubber powder and the surface of the expanded and vitrified micro-bead can be improved by the linear phenolic resin, the retention of the water in the concrete is reduced, the low-temperature condensation of the water is prevented, and the concrete is cracked.

Detailed Description

Preparation example of waste Material

In the following preparation examples, the diethylenetriamine pentamethylenephosphonic acid is selected from Shandong Poppon import and export company, and the model is BP-8W 26; the polyisobutenyl succinimide is selected from Shandong Denno New Material science and technology GmbH, model number T154161; the polyacrylamide is selected from Sanmei chemical engineering and technology Co., Ltd, Dongguan, and has a model of FQ-JB 01; the melamine formaldehyde resin is selected from Shandong Wangshi New Material science and technology Limited, with the product number of WS-10; the nanometer titanium dioxide is selected from Jiangsu Tianxing New Material Co., Ltd, and the model is TPP-A12.

Preparation example 1: (1) crushing, grinding and sieving construction waste by a jaw crusher to prepare waste micro powder, soaking the waste micro powder in a mixed solution prepared from diethylenetriamine pentamethylenephosphonic acid and polyisobutylene succinimide, filtering, drying the waste micro powder, calcining for 3 hours at 1000 ℃, and cooling, wherein the mass ratio of the diethylenetriamine pentamethylenephosphonic acid to the polyisobutylene succinimide is 1: 0.4;

(2) air-drying the straws, smashing into 3cm, soaking in 0.07% polyacrylamide aqueous solution, adding waste micro powder, mixing uniformly, drying, grinding, and preparing into waste material, wherein the mass ratio of the straws to the waste micro powder is 0.1: 1.

Preparation example 2: (1) crushing, grinding and sieving construction waste by a jaw crusher to prepare waste micro powder, soaking the waste micro powder in a mixed solution prepared from diethylenetriamine pentamethylenephosphonic acid and polyisobutylene succinimide, filtering, drying the waste micro powder, calcining for 4 hours at 1100 ℃, and cooling, wherein the mass ratio of the diethylenetriamine pentamethylenephosphonic acid to the polyisobutylene succinimide is 1: 0.8;

(2) air-drying the straws, smashing into 3cm, soaking in 0.01% polyacrylamide aqueous solution by mass percent, adding waste micro powder, uniformly mixing, drying and grinding to prepare a waste material, wherein the mass ratio of the straws to the waste micro powder is 0.3: 1.

Preparation example 3: the difference from preparation example 1 is that step (2) was not performed.

Preparation example 4: the difference from preparation example 1 is that the straw was not immersed in the polyacrylamide solution.

Preparation example 5: the difference from the preparation example 1 is that the straws are pretreated as follows: soaking the straws in a sodium hydroxide solution with the mass percentage concentration of 1.5% for 8 hours, drying, then placing the dried straws in a mixed solution prepared from 0.3kg of melamine formaldehyde resin, 0.04kg of nano titanium dioxide and 0.8kg of ethanol, vacuum-soaking the straws for 2 hours under the pressure of-0.1 MPa, drying, and then uniformly spraying a sodium silicate solution with the mass percentage concentration of 1% on the surfaces of the straws, wherein the spraying amount of the sodium silicate solution is 10% of the mass of the straws.

Preparation example 6: the difference from example 1 is that the straw was pretreated as follows: soaking the straws in a sodium hydroxide solution with the mass percentage concentration of 1.5% for 10 hours, drying, then placing the dried straws in a mixed solution prepared from 0.5kg of melamine formaldehyde resin, 0.08kg of nano titanium dioxide and 1kg of ethanol, vacuum-soaking the straws for 2 hours under-0.1 MPa, drying, and then uniformly spraying a sodium silicate solution with the mass percentage concentration of 2% on the surfaces of the straws, wherein the spraying amount of the sodium silicate solution is 20% of the mass of the straws.

Preparation example 7: the difference from preparation example 5 is that the melamine formaldehyde resin was not added to the mixed solution.

Preparation example 8: the difference from preparation example 5 is that the nano titania was not added to the mixed solution.

Preparation example 9: the difference from preparation example 5 was that the sodium silicate solution was not sprayed.

Examples

The sources of the respective raw materials in the following examples are shown in table 1.

Table 1 examples the sources of the various feedstocks

Example 1: the raw material composition of the recycled concrete is shown in Table 2, the waste material in the Table 2 is selected from preparation example 1, the particle size of the waste material is 0.15-3mm and 5-10mm, the mass ratio of the waste material with the particle size of 0.15-3mm to the waste material with the particle size of 5-10mm is 1.5:4.2, the cement is sulphoaluminate cement, the 28d compressive strength is 52.5MPa, the crushed stone is continuous graded crushed stone with the particle size of 5-20mm, the crushing index is less than or equal to 6 percent, and the apparent density is 1700Kg/m³Bulk density 1200Kg/m³The mud content is less than 0.5 percent, the water content is 0.1 percent, the mud block content is less than 0.1 percent, the sand is machine-made sand, the grain diameter is 1000 meshes, the mud content is 0.01 percent, and the apparent density is 1800Kg/cm³The bulk density is 1.6Kg/cm³The water content is 0.1%, the admixture comprises a high-efficiency water reducing agent, an organic silicon water repellent and silica fume in a mass ratio of 0.1:2:10, the high-efficiency water reducing agent is a polycarboxylic acid water reducing agent, and EPS particles are pretreated as follows: mixing EPS particles, polyvinyl alcohol, sulphoaluminate cement and water according to the mass ratio of 1:0.5:3:1.5, and drying.

The preparation process of the waste recycled concrete comprises the following steps:

Table 2 raw material amounts of concrete in examples 1 to 4

Examples 2 to 4: the waste recycled concrete is different from the concrete of example 1 in that the raw material amount is shown in table 2.

Example 5: the concrete recycled from waste is different from the concrete of example 1 in that the preparation examples of waste materials are shown in table 3.

Table 3 preparation of waste material options in examples 5-10

Examples	Preparation example
		Example 5	Preparation example 2
Example 6	Preparation example 5
		Example 7	Preparation example 6
Example 8	Preparation example 7
		Example 9	Preparation example 8
Example 10	Preparation example 9

Example 11: the recycled concrete of the waste is different from the concrete of the example 6 in that the mixed expanded and vitrified micro-beads are pretreated by the following steps: (1) soaking waste rubber powder ground to have the particle size of 100nm in a phenol-formaldehyde novolac resin acetone solution, wherein the mass ratio of the waste rubber powder to the phenol-formaldehyde novolac resin is 1:0.3, and drying under reduced pressure at the temperature of 55 ℃ and the pressure of 0.01 MPa; (2) uniformly mixing 1kg of silane coupling agent, 0.03kg of hexamethylenetetramine and 0.8kg of water to prepare spraying liquid, adding the waste rubber powder prepared in the step (1), uniformly mixing, uniformly spraying the mixture on 1kg of expanded and vitrified micro bubbles, heating to 150 ℃, preserving the heat for 10min, cooling, wherein the mass ratio of the expanded and vitrified micro bubbles to the waste rubber powder to the spraying liquid is 1:0.2:0.1, and the silane coupling agent is KH-560.

Example 12: the recycled concrete of the waste is different from the concrete of the example 6 in that the mixed expanded and vitrified micro-beads are pretreated by the following steps: (1) soaking waste rubber powder ground to have the particle size of 150nm in a phenolic novolac resin acetone solution, wherein the mass ratio of the waste rubber powder to the phenolic novolac resin is 1: 0: 5, and drying under reduced pressure at the temperature of 55 ℃ and the pressure of 0.01 MPa;

(2) uniformly mixing 2kg of silane coupling agent, 0.05kg of hexamethylenetetramine and 1kg of water to prepare spraying liquid, adding the waste rubber powder prepared in the step (1), uniformly mixing, uniformly spraying the mixture on 1kg of expanded and vitrified micro bubbles, heating to 180 ℃, keeping the temperature for 15min, and cooling, wherein the mass ratio of the expanded and vitrified micro bubbles to the waste rubber powder to the spraying liquid is 1:0.4:0.3, and the silane coupling agent is KH-560.

Example 13: a waste recycled concrete, which is different from example 11 in that the waste rubber powder is not impregnated with the phenol novolac resin in the pretreatment of the vitrified small balls.

Example 14: a waste recycled concrete, which is different from the concrete prepared in the example 11 in that the expanded and vitrified small balls are pretreated by the following steps: uniformly mixing 2kg of linear phenolic resin, 0.05kg of hexamethylenetetramine and 1kg of water to prepare a spraying liquid, uniformly spraying the spraying liquid on 1kg of expanded and vitrified micro bubbles, heating to 180 ℃ while stirring, preserving the heat for 20min, and cooling, wherein the mass ratio of the expanded and vitrified micro bubbles to the spraying liquid is 1: 0.3.

Comparative example

Comparative example 1: a waste recycled concrete, which is different from example 1 in that the waste material is selected from preparation example 3.

Comparative example 2: a waste recycled concrete, which is different from example 1 in that the waste material is selected from preparation example 4.

Comparative example 3: the concrete recycled from wastes is different from the concrete of example 1 in that no expanded and vitrified small balls are added.

Comparative example 4: a waste recycled concrete, which differs from example 1 in that no EPS granules are added.

Comparative example 5: a preparation method of pervious concrete comprises the following steps:

(1) first, a composite gel material is prepared, taking 100kg of the composite gel material as an example.

Respectively weighing 75kg of cement, 22kg of concrete ash and 3kg of styrene-acrylic emulsion powder, sequentially adding the cement, the concrete ash and the styrene-acrylic emulsion powder into a mixer, and fully stirring to obtain a composite cementing material for later use; the cement is 42.5 or 52.5 grade ordinary portland cement, the concrete ash is fine powder which is ground after the waste concrete is crushed, and the specific surface area is more than or equal to 500m 2/kg;

(2) preparing pervious concrete; respectively weighing 200kg of the composite cementing material and 714kg of recycled concrete aggregate, putting the materials into a stirrer to be uniformly stirred, then adding 86kg of water, and fully and uniformly stirring again to realize the processes of pouring, leveling and curing to obtain the pervious concrete, wherein the recycled concrete aggregate is waste concrete, and the particle size of the recycled concrete aggregate is 5-10mm after crushing, impurity removal and cleaning.

Performance test

Concrete was prepared according to the methods in the examples and comparative examples, and the properties of the concrete were measured with reference to the following methods, and the results of the measurement are recorded in table 4.

1. Compressive strength and flexural strength: the detection is carried out according to GB/T50081-2002 standard of test methods for mechanical properties of common concrete.

2. Water permeability coefficient: and (4) detecting according to GB/T25993-2010 specification of a standard permeable cement concrete permeability coefficient test device.

3. Mass loss rate and dynamic elastic modulus loss rate: the method is carried out according to a quick freezing method of an anti-freezing test in GBJ82-85 'test method for long-term performance and durability of common concrete', a test piece is maintained for 24 days and then is soaked in water with the temperature of 15-20 ℃, the height difference between the water surface and the top surface of the test piece is 20mm when the test piece is soaked, each freezing-thawing cycle is hard to complete within 2-4h, the central temperature of the test piece is respectively controlled to be (-17 +/-20) DEG C and (8 +/-20) DEG C, the size of the test piece for measuring the relative dynamic elasticity value and the mass loss is 100mm multiplied by 400mm, the test piece is soaked for 4 days and then is taken out, the surface moisture is wiped and weighed to obtain an initial mass M0, the test piece is taken out after 300 freezing-thawing cycles, the moisture on the surface of the test piece is wiped and weighed to obtain the mass Mn of the test piece after 300 freezing-thawing cycles, and the loss rate is calculated according to the following formula: x (%) ═ Mo — Mn/Mo, compressive strength loss rate was calculated according to the following formula: n (%) ═ En/Eo, where En is the compressive strength after 300 freeze-thaw cycles and Eo is the initial compressive strength.

5. Corrosion resistance: preparing a concrete test piece according to GB/T50081-2012 standard of a method for testing mechanical properties of common concrete, wherein the size of the concrete test piece is 100mm multiplied by 100mm, curing for a certain time, and then detecting as follows: weighing the mass of a test piece, placing the test piece in an acid solution with the pH value of 3.5, placing for 28 days, weighing the mass of the test piece, and calculating the mass loss rate before and after detection, namely the acid corrosion rate; secondly, weighing the test piece, placing the test piece in an alkaline solution with the pH of 8.5, placing the test piece for 28 days, weighing the mass of the test piece, and calculating the mass loss rate before and after detection, namely the alkaline corrosion rate.

Table 4 concrete performance testing of waste recycling

As can be seen from the data in Table 4, the concrete prepared in examples 1-5 has high permeability coefficient and high compressive strength, which indicates that the concrete prepared from the waste material prepared by the method of the present application has improved permeability.

The waste materials prepared in preparation examples 5 and 6 are respectively adopted in example 6 and example 7, and the straws are pretreated by components such as melamine formaldehyde resin in the preparation examples 5 and 6 compared with the preparation example 1, and the data in the table 4 show that compared with the example 1, the breaking strength of the concrete is enhanced, the freezing resistance is improved, and the acid and alkali corrosion resistance is further improved.

Example 8 using the waste material of preparation example 7, wherein the melamine formaldehyde resin was not added when the straw was pretreated, the acid corrosion rate and the alkaline corrosion rate of the concrete were increased, and the compressive strength and the mass loss rate were increased after 300 times of freeze-thawing, compared to example 6, indicating that the melamine formaldehyde resin can enhance the acid and alkali corrosion resistance of the straw and improve the freeze-thaw resistance of the concrete.

In example 9, the waste material prepared in preparation example 8 was used, and when the straw was pretreated, the nano titanium dioxide was not added, and compared with example 6, the concrete prepared in example 9 had little change in compressive strength and flexural strength, but its acid and alkali corrosion resistance was reduced, and its freeze-thaw resistance was reduced.

In example 10, the waste material prepared in preparation example 9 was used, and since no sodium silicate solution was used in straw pretreatment, the concrete prepared in example 10 showed significantly increased acidic corrosion rate and alkaline corrosion rate compared to example 6, indicating that the sodium silicate solution can improve the corrosion resistance of straw fiber.

In the examples 11 and 12, the components such as waste rubber powder and linear phenolic resin are used for pretreating the expanded and vitrified micro-beads, compared with the example 6, the water permeability coefficient of the concrete is not changed remarkably, but the freeze-thaw resistance of the concrete is improved obviously, and the mass loss rate and the compressive strength loss rate of the concrete are further reduced after 300 freeze-thaw cycles.

In example 13, compared to example 11, when the expanded and vitrified small balls were pretreated, the mass loss rate and the compressive strength loss rate of the concrete prepared in example 13 were increased and the acid and alkali corrosion resistance was decreased after 300 freeze-thaw cycles without using the phenol novolac resin.

In example 14, compared with example 11, when the expanded and vitrified small balls were pretreated, the freeze-thaw resistance of the concrete was deteriorated without using the waste rubber powder.

Comparative example 1 compared with example 1, the permeability coefficient of the prepared concrete was significantly reduced without mixing the straw with the construction waste micropowder, and the flexural strength was weakened.

Comparative example 2 compared with example 1, it was difficult to uniformly disperse the straw and the waste fine powder without immersing the straw in the polyacrylamide solution, and the flexural strength of the concrete was reduced and the water permeability coefficient was decreased.

Compared with the example 1, the concrete in the comparative example 3 has reduced water permeability coefficient, the concrete in the comparative example 4 has reduced breaking strength and reduced freezing and thawing effect, and the comparative example 3 and the comparative example 4 have no expanded and vitrified micro-beads and EPS particles added respectively.

Comparative example 5 is a pervious concrete prepared by the prior art, which has a coefficient inferior to that of the present application, and which has poor freeze-thaw resistance and insufficient corrosion 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 concrete for recycling the waste is characterized by comprising the following components in parts by weight: 300 portions of cement-;

the waste material is made by the following method:

2. The waste recycling concrete of claim 1, wherein the straw is pretreated by: soaking the straws in a sodium hydroxide solution for 8-16h, drying, then placing the dried straws in a mixed solution prepared from 0.3-0.5 part by weight of melamine formaldehyde resin, 0.04-0.08 part by weight of nano titanium dioxide and 0.8-1 part by weight of ethanol, vacuum-soaking, drying, and then uniformly spraying a sodium silicate solution with the mass percentage concentration of 1-2% on the surfaces of the straws, wherein the spraying amount of the sodium silicate solution is 10-20% of the mass of the straws.

3. The waste recycling concrete according to claim 1, wherein the vitrified micro bubbles are pretreated by:

4. The concrete for recycling waste as claimed in claim 3, wherein the particle size of the expanded and vitrified micro bubbles is 30-50 mesh, the particle size of the waste rubber powder is 100-150nm, and the silane coupling agent is KH-560.

5. The waste recycled concrete according to claim 1, wherein the EPS particles are pretreated by: mixing EPS particles, polyvinyl alcohol, sulphoaluminate cement and water according to the mass ratio of 1:0.3-0.5:2-3:1-1.5, and drying.

6. The waste recycling concrete according to claim 1, wherein the waste material is composed of waste material with a particle size of 0.15-3mm and waste material with a particle size of 5-10mm, and the mass ratio of the waste material with a particle size of 0.15-3mm to the waste material with a particle size of 5-10mm is 1-1.5: 3.7-4.2.

7. The concrete recycled by wastes according to claim 1, wherein the admixture comprises a high-efficiency water reducing agent, an organosilicon water repellent and silica fume, and the mass ratio of the high-efficiency water reducing agent to the organosilicon water repellent to the silica fume is 0.1-0.3:2-5: 10-20.

8. The concrete for recycling waste as claimed in claim 1, wherein the crushed stone is a continuous graded crushed stone of 5-20mm, the crushing index is less than or equal to 6%, the mud content is less than 0.5%, and the mud block content is less than 0.1%.

9. The concrete for recycling wastes as claimed in claim 1, wherein the sand is machine-made sand with a particle size of 800-1000 meshes and an apparent density of 1800-2000Kg/cm³。

10. The process for preparing the concrete for recycling waste of any one of claims 1 to 9, comprising the steps of: