CN111217571A - Method for treating ceramsite for concrete and pervious concrete with ceramsite as coarse aggregate - Google Patents

Abstract

The invention provides a method for treating ceramsite for concrete and pervious concrete with the ceramsite as a coarse aggregate, wherein the ceramsite obtained by the method can effectively reduce the water absorption rate of the ceramsite and improve the cylinder pressure strength of the ceramsite, and the ceramsite used as the coarse aggregate for the pervious concrete can obviously improve the strength of the pervious concrete and the anti-stripping performance of the ceramsite. The processing method comprises the following steps: 1) handle 1m³Placing the ceramsite into a treatment container, and vacuumizing under the vacuum degree of 0.2-0.5 MPa; 2)108 dissolving the rubber powder in water to prepare a latex aqueous solution; adding ordinary Portland cement, a first water reducing agent and a first water retention thickening agent to prepare self-leveling cement paste with the thickness of 0.3-0.5m³And injecting into the treatment container, stirring for 180-240s under the condition of keeping the vacuum degree of 0.2-0.5MPa, separating out ceramsite, naturally drying, and preserving moisture for 28d for later use.

Description

Method for treating ceramsite for concrete and pervious concrete with ceramsite as coarse aggregate

Technical Field

The invention relates to a method for treating ceramsite for concrete and pervious concrete with the ceramsite as a coarse aggregate, and belongs to the technical field of road building materials.

Background

The pervious concrete, also called porous concrete, non-sand or less-sand concrete and pervious terrace, is a porous light concrete mixed by coarse aggregate, cement, reinforcing agent, water-reducing agent and water, and is characterized by that the surface of coarse aggregate is coated with a thin layer of cement paste, and mutually bonded to form a cellular structure with uniformly distributed pores, so that it has the characteristics of air permeability, water permeability and light weight. The pervious concrete is developed and used by countries such as Europe, America, Japan and the like aiming at the road surface defects of the original urban roads, can make rainwater flow into the ground, effectively supplement underground water, relieve some urban environmental problems such as rapid decline of the underground water level of the city and the like, and can effectively eliminate the harm of oil compounds on the ground and the like to environmental pollution; the composite material is an excellent paving material which can protect underground water, maintain ecological balance and relieve urban heat island effect, is beneficial to the benign development of human living environment and the work of urban rainwater management, water pollution prevention and control and the like, and has special important significance.

The pervious concrete needs to maintain a certain through porosity (11% -17%) to meet the basic requirements of water permeability, and also needs to meet certain requirements of compressive strength, bending strength, wear resistance, anti-stripping performance and beauty. Therefore, when the pervious concrete is prepared, in addition to selecting proper raw materials, the strength and the porosity are ensured through the design of the mixing proportion, the preparation process and special additives. Generally, the coarse aggregate is mainly single-particle-grade or discontinuous-particle-grade coarse aggregate as a framework, and portland cement, ordinary portland cement and other portland cement can be selected as cement. The existing reinforcing agents for pervious concrete are of two types, one type is that the reinforcing agent contains active SiO₂Superfine admixture (such as silica fume) with the content of more than or equal to 85 percent; the polymer glue powder or polymer emulsion, such as water-based acrylic emulsion, styrene-butadiene emulsion, EVA emulsion and the like, mainly has the function of improving the bonding force between cement-based slurry and aggregate and the bonding strength between the slurry and the slurry.

At present, most of conventional coarse aggregates for pervious concrete are machine-made broken stones, building solid waste recycled aggregates, broken waste glass cullet and the like. On squares or sidewalks in parks, the pervious concrete not only needs good water permeability, certain compressive and flexural strength and good anti-stripping performance, but also needs color beauty and body-building walking comfort to bring people with beautiful enjoyment. However, the pervious concrete prepared by the aggregate has irregular aggregate particle type, so that the pervious concrete surface layer is not beautiful and irregular even if colored pigment or protective layer is provided, especially for pervious concrete with exposed aggregate on the surface layer. The spherical light artificial ceramsite is used as the coarse aggregate, so that the pervious concrete has good integrity and high uniformity, the surface layer of the constructed concrete is more attractive, the walking is comfortable, and the body can be built. However, when the ceramsite is used as the coarse aggregate, the ceramsite has a porous structure, low cylinder pressure strength and high water absorption, so that the pervious concrete exists during productionThe water-cement ratio fluctuation is large, the binding strength between the ceramsite interface and the cement paste is low, so that the ceramsite is easy to peel off and fall off from the pervious concrete, and the appearance and the durability are influenced. The existing ceramsite water-permeable concrete technology mainly aims at improving the compression strength and the breaking strength. For example: chinese patent document CN105272067A describes a lightweight pervious concrete containing ceramsite, and the concrete preparation ratio (kg/m)³) The following were used: 130-150 parts of mixing water, 410-450 parts of cement, 990-1000 parts of ceramsite and 1.11-1.80 parts of additive, wherein the ceramsite is coal gangue ceramsite with the grain size of 5-10mm and continuous gradation, the grain shape is spherical, and the stacking density grade of the coal gangue ceramsite is 900kg/m³～950kg/m³The compact bulk density is 980kg/m³～1030kg/m³The apparent density is 1700kg/m³～1800kg/m³The porosity of the pervious concrete is 16 percent, and the 28d strength is 28.5 MPa. Chinese patent document CN105236878A introduces a ceramsite concrete permeable pavement product material, which comprises the following raw materials in percentage by mass: 15-20% of Portland cement or sulphoaluminate cement, 40-60% of high-strength ceramsite, 10-35% of ceramsite calcined fly ash, 0.5-1.5% of fiber, 5-10% of calcined lime, 0.1-1% of water reducing agent, 0.05-0.5% of water retaining agent and 0.1-0.5% of polystyrene foam, and has the advantages of good water permeability of the material, high strength (the 28d strength reaches 40-50MPa), good long-term use and the like, but the ceramsite water permeable concrete product needs to be carried out under the condition of heat curing at 80-100 ℃, needs certain external temperature conditions and has limitations. The compression strength of the ceramsite pervious concrete prepared by the conventional construction method is generally 20MPa-30MPa, and the bending tensile strength is generally not more than 3.0 MPa. The compression strength and the rupture strength of the ceramsite permeable concrete still have a space for improving. In addition, the problem of anti-stripping of coarse aggregates (ceramsite) in the pervious concrete by the conventional construction method is still the problem to be mainly solved for the engineering quality.

As is well known, the bonding strength of the interface between cement paste and aggregate (ceramsite) is the key of the compression resistance, the folding resistance and the ceramsite anti-stripping performance of the pervious concrete. The interfacial bonding strength is related to not only the water cement ratio but also the bonding structure state of the cement paste and the aggregate. Chinese patent document CN108483963A describes a particle pretreatment coating technique for reducing the water absorption of ceramsite, which comprises mixing surfactant (the molecular structure of the surfactant contains polar hydrophilic groups such as carboxylic acid, sulfonic acid, sulfuric acid, amino or amino) with water, spraying the mixture on the surface of the ceramsite, and coating the ceramsite with sulphoaluminate cement slurry to form a hardened slurry layer of 1-2mm on the surface of the ceramsite, thereby improving the cylinder pressure strength of the ceramsite and reducing the water absorption of the ceramsite. The inventors have not been satisfactory to use this pre-treatment coating technique to treat ceramsite and then to use it in pervious concrete. The inventor researches and considers that the ceramsite has an internal space structure with open pores and closed pores, the gaps of the open pores are often larger, the ceramsite is wetted only by spraying surfactant aqueous solution, and then the ceramsite is coated by stirring sulphoaluminate cement slurry to cover the ceramsite, so that the bonding strength between the cement slurry and the surface of the ceramsite has certain limitation, in addition, the open pores of the ceramsite are filled with the surfactant aqueous solution and/or air, and the cylinder pressure strength of the ceramsite also has a space for improving.

Disclosure of Invention

In view of the above, the present invention provides a method for treating ceramsite for concrete and a permeable concrete using the ceramsite as a coarse aggregate, wherein the ceramsite obtained by the method can effectively reduce the water absorption rate of the ceramsite and improve the cylinder pressure strength of the ceramsite, and the ceramsite used as the coarse aggregate for the permeable concrete can significantly improve the strength of the permeable concrete and the anti-stripping performance of the ceramsite.

Specifically, the method comprises the following technical scheme:

according to a first aspect of the present invention, there is provided a method for treating ceramsite for concrete, comprising the steps of:

1) the water absorption rate of 24h is 8 to 12 percent, and the bulk density is 600 to 1000kg/m³1m with the cylinder pressure intensity of 4.0-8.0MPa³Placing the ceramsite into a treatment container, and vacuumizing for 10-30min under the vacuum degree of 0.2-0.5 MPa;

2) stirring, mixing and dissolving 108 kg of rubber powder in 100kg of water according to the proportion of 0.5-1.0kg of the rubber powder to prepare latex aqueous solution; controlling the water cement ratio to be 0.30-0.35, adding 52.5-grade ordinary portland cement, a first water reducing agent and a first water-retaining thickening agentPreparing self-leveling cement paste with the thickness of 0.3-0.5m³Injecting the mixture into the treatment container, stirring for 180-240s under the condition of keeping the vacuum degree of 0.2-0.5MPa, naturally drying after separating out the ceramsite, wherein the thickness of a cement layer coated on the surface of the ceramsite is 2-3mm, and keeping moisture for 28d for later use, wherein the self-leveling slurry refers to the GB50119-2013 standard, and the fluidity of the cement neat paste is 250-300 mm.

The first water reducer and the first water retention thickener can be experimentally determined by those skilled in the art according to the prior art, so as to obtain the self-leveling cement slurry with good fluidity and water retention. Preferably, the first water reducing agent is a polycarboxylic acid liquid water reducing agent with the solid content of 8% -12%, and the mixing amount is 0.13% -0.24% of the using amount of the 52.5-level ordinary portland cement; the first water-retaining thickener is methyl cellulose ether (CMC) or hydroxypropyl methyl cellulose ether (HPMC), and the dosage of the first water-retaining thickener is 0.002% -0.008% of the dosage of 52.5-grade ordinary portland cement. Of these, CMC and HPMC are both powders, which are known and used in the art and are commercially available.

In the invention, the doping amount is the folding and fixing doping amount, namely the doping amount calculated by the solid substance contained in the doped substance.

The separation can be carried out by means customary in the art, for example by separating off the haydite through a 5mm slot.

According to the second aspect of the invention, the invention also provides pervious concrete with the ceramsite prepared by the treatment method as a coarse aggregate.

Preferably, the pervious concrete comprises the following components in parts by mass:

100-130 parts of water, 350-450 parts of cement, 500-900 parts of coarse aggregate and 15-25 parts of composite reinforcing agent, wherein:

the cement is ordinary 42.5 or 52.5-grade portland cement, and the coarse aggregate is spherical ceramsite with the particle size of 5-10 mm;

the composite reinforcing agent comprises the following components in percentage by mass:

20 to 30 percent of latex powder

1 to 2 percent of defoaming agent

3 to 10 percent of second water-retaining thickening agent

5 to 10 percent of cement reinforcing agent

Balance of carrier

The carrier is silica fume and/or slag micro powder;

the mass portion of the composite reinforcing agent is calculated by the solid matter contained in the composite reinforcing agent; the mass percentage of the composite reinforcing agent is calculated by the solid substances contained in various compositions;

the strength grade of the pervious concrete is C20-C30, and the construction slump is 30-50 mm.

The silica fume and the slag micropowder are all known and commonly used in the field, and preferably, the specific surface area of the slag micropowder is 600-800m²Per kg; the specific surface area of the silica fume is 15-27m²The content of silicon dioxide is more than 92 percent, and the 28d activity index is more than or equal to 85 percent.

As a conventional means in the field, a second water reducing agent can be added into the pervious concrete to ensure the construction slump. The amount of the second water reducing agent can be determined experimentally. The second water reducing agent can be selected from known and common substances, such as melamine resin liquid water reducing agent and polycarboxylic acid liquid water reducing agent, and the two water reducing agents are colorless or light yellow liquid and do not affect the color of the pervious concrete. Preferably, the second water reducing agent is a polycarboxylic acid water reducing agent, and the dosage of the second water reducing agent is 0.7-1 part by mass based on solid matters contained in the polycarboxylic acid water reducing agent; or the second water reducing agent is melamine resin liquid water reducing agent, and the dosage is 2.45-3.5 parts by mass based on solid matters contained in the melamine resin liquid water reducing agent.

It is further preferred that the first and second liquid crystal compositions,

the latex powder is acrylate copolymer, and can improve the bonding capability of cement slurry in concrete in pervious concrete, reduce bleeding of the concrete and improve the anti-cracking and anti-breaking capabilities of the concrete. The bonding strength of the cement-based slurry added with the acrylate copolymer emulsion can be improved by more than 3 times, and the compactness (impermeability) of the slurry is improved by more than 1.5 times;

the defoaming agent is a mixture of tributyl phosphate, polyether liquid defoaming agent and siloxane liquid defoaming agent in a mass ratio of 1 (1-2) to (1-2). The defoaming agent is added, so that bubbles in the cement-based slurry under the action of surfactants such as latex powder, chemical additives and the like can be eliminated in the concrete stirring process, and the interface bonding capability between the cement slurry and the aggregate is effectively improved;

the second water-retaining thickening agent is a mixture of CMC, sodium alginate and starch ether with the mass ratio of 1 (1-1.5) to 1-1.5;

the cement reinforcing agent is prepared from the following components in percentage by mass of 1: (1-1.5): (1-2): (1-2) a mixture of sodium thiocyanate, tetrahydroxyethylethylenediamine (hereinafter, THEED), triethanolamine (hereinafter, TEA) and triisopropanolamine (hereinafter, TIPA);

the mass ratio is a mass ratio of solid substances contained in the mixture components.

Still more preferably, the starch ether is carboxymethyl starch and/or guar gum ether.

The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:

(1) the processing method of the invention treats the ceramsite by the self-leveling cement slurry under the vacuum state, forms a cement slurry coating layer on the surface of the ceramsite, and simultaneously can well fill the cement slurry in the open pore of the ceramsite, and the hardened cement slurry is like a plurality of wedges, thus playing a role of filling a skeleton and enhancing the cylinder pressure strength of the ceramsite, and simultaneously greatly enhancing the bonding effect of the cement slurry and the surface of the ceramsite, thereby greatly enhancing the anti-stripping performance, the compressive strength and the bending tensile strength of the ceramsite. The time and the vacuum degree of the vacuum pumping can be determined by the technicians in the field through experiments according to the specific conditions of equipment (such as the power and the performance of an air pump) and the ceramsite, and the concrete judgment method can be that the open pores of the ceramsite fully absorb the cement slurry as a judgment standard: randomly extracting a plurality of pretreated porcelain granules from the stirring container, naturally drying the porcelain granules, then smashing the porcelain granules by using an iron hammer, and observing the condition that the cement paste penetrates into the open pores; the ceramic particle opening is filled with cement slurry by adjusting the vacuum degree and the processing time in the processing container.

(2) The invention adopts the multi-component composite reinforcing agent, combines the effects in various aspects, and improves the compressive strength and the bending tensile strength of the pervious concrete.

Detailed Description

In order to make the technical solutions and advantages of the present invention more clear, embodiments of the present invention will be described in further detail below.

According to a first aspect of the present invention, there is provided a method for treating ceramsite for concrete, comprising the steps of:

1) the water absorption rate of 24h is 8 to 12 percent, and the bulk density is 600 to 1000kg/m³1m with the cylinder pressure intensity of 4.0-8.0MPa³Placing the ceramsite into a treatment container, and vacuumizing for 10-30min under the vacuum degree of 0.2-0.5 MPa;

2) stirring, mixing and dissolving 108 kg of rubber powder in 100kg of water according to the proportion of 0.5-1.0kg of the rubber powder to prepare latex aqueous solution; controlling the water cement ratio to be 0.30-0.35, adding 52.5-grade ordinary portland cement, a first water reducing agent and a first water-retaining thickener to prepare self-leveling cement paste with the thickness of 0.3-0.5m³Injecting the mixture into the treatment container, stirring for 180-240s under the condition of keeping the vacuum degree of 0.2-0.5MPa, naturally drying after separating out the ceramsite, wherein the thickness of a cement layer coated on the surface of the ceramsite is 2-3mm, and keeping moisture for 28d for later use, wherein the self-leveling slurry refers to the GB50119-2013 standard, and the fluidity of the cement neat paste is 250-300 mm.

The first water reducer and the first water retention thickener can be experimentally determined by those skilled in the art according to the prior art, so as to obtain the self-leveling cement slurry with good fluidity and water retention. Preferably, the first water reducing agent is a polycarboxylic acid liquid water reducing agent with the solid content of 8% -12%, and the mixing amount is 0.13% -0.24% of the using amount of the 52.5-level ordinary portland cement; the first water-retaining thickener is CMC or HPMC, and the mixing amount is 0.002% -0.008% of the dosage of 52.5-grade ordinary portland cement.

According to the second aspect of the invention, the invention also provides pervious concrete with the ceramsite prepared by the treatment method as a coarse aggregate.

Preferably, the pervious concrete comprises the following components in parts by mass:

100-130 parts of water, 350-450 parts of cement, 500-900 parts of coarse aggregate and 15-25 parts of composite reinforcing agent, wherein:

the cement is ordinary 42.5 or 52.5-grade portland cement, and the coarse aggregate is spherical ceramsite with the particle size of 5-10 mm;

the composite reinforcing agent comprises the following components in percentage by mass:

20 to 30 percent of latex powder

1 to 2 percent of defoaming agent

3 to 10 percent of second water-retaining thickening agent

5 to 10 percent of cement reinforcing agent

Balance of carrier

The carrier is silica fume and/or slag micro powder;

the mass portion of the composite reinforcing agent is calculated by the solid matter contained in the composite reinforcing agent; the mass percentage of the composite reinforcing agent is calculated by the solid substances contained in various compositions;

the strength grade of the pervious concrete is C20-C30, and the construction slump is 30-50 mm.

The silica fume and the slag micropowder are all known and commonly used in the field, and preferably, the specific surface area of the slag micropowder is 600-800m²Per kg; the specific surface area of the silica fume is 15-27m²The content of silicon dioxide is more than 92 percent, and the 28d activity index is more than or equal to 85 percent.

As a conventional means in the field, a second water reducing agent can be added into the pervious concrete to ensure the construction slump. The amount of the second water reducing agent can be determined experimentally. The second water reducing agent can be selected from known and common substances, such as melamine resin liquid water reducing agent and polycarboxylic acid liquid water reducing agent, and the two water reducing agents are colorless or light yellow liquid and do not affect the color of the pervious concrete. Preferably, the second water reducing agent is a polycarboxylic acid water reducing agent, and the dosage of the second water reducing agent is 0.7-1 part by mass based on solid matters contained in the polycarboxylic acid water reducing agent; or the second water reducing agent is melamine resin liquid water reducing agent, and the dosage is 2.45-3.5 parts by mass based on solid matters contained in the melamine resin liquid water reducing agent.

It is further preferred that the first and second liquid crystal compositions,

the latex powder is acrylate copolymer, and can improve the bonding capability of cement slurry in concrete in pervious concrete, reduce bleeding of the concrete and improve the anti-cracking and anti-breaking capabilities of the concrete. The bonding strength of the cement-based slurry added with the acrylate copolymer emulsion can be improved by more than 3 times, and the compactness (impermeability) of the slurry is improved by more than 1.5 times;

the defoaming agent is a mixture of tributyl phosphate, polyether liquid defoaming agent and siloxane liquid defoaming agent in a mass ratio of 1 (1-2) to (1-2). The defoaming agent is added, so that bubbles in the cement-based slurry under the action of surfactants such as latex powder, chemical additives and the like can be eliminated in the concrete stirring process, and the interface bonding capability between the cement slurry and the aggregate is effectively improved;

the second water-retaining thickening agent is a mixture of CMC, sodium alginate and starch ether with the mass ratio of 1 (1-1.5) to 1-1.5;

the cement reinforcing agent is prepared from the following components in percentage by mass of 1: (1-1.5): (1-2): (1-2) a mixture of sodium thiocyanate, THEED, TEA and TIPA;

the mass ratio is a mass ratio of solid substances contained in the mixture components.

Still more preferably, the starch ether is carboxymethyl starch and/or guar gum ether.

In the following examples, the raw material conditions involved are as follows:

1) the 42.5 or 52.5 grade ordinary portland cement is produced by Shandong Yizhou cement group company, and the 42.5 or 52.5 grade white portland cement is produced by Zibo Hua Xue building materials Co.

2)5-10mm spherical ceramsite produced by Shandong Linyi purple gold ceramsite factory with 24h water absorption of 8-12% and bulk density of 600-1000kg/m³The cylinder pressure strength is 4.0-8.0 MPa.

3) Water reducing agent: melamine resin liquid water reducing agent with solid content of 35% produced by Suzhou Xingbang chemical building materials Co; the solid content of the polycarboxylic liquid water reducing agent is 10 percent, and the water reducing rate is 22 to 28 percent.

4) Defoaming agent: tributyl phosphate, liquid, chemical reagent, Shandong Linyi chemical industry market; the siloxane liquid defoamer PD352-C (the content is 50 percent) and the polyether liquid defoamer PD360 (the content is 40 percent) are both produced by Beijing Baochen union GmbH.

5) Emulsion powder: acrylate copolymer

6011A, powder, bulk density 550 + -50 g/L, manufactured by Beijing Baochen union GmbH;

6) the specific surface area of the slag micro powder, the Lida mineral powder plant in the Luo village of Linyi City, Shandong province is 600-800m²Per kg; silica fume with specific surface area of 15-27m²The content of silicon dioxide is more than 92 percent, the 28d activity index is more than or equal to 85 percent, and the Shandong Boken silicon material Co.

7) Sodium thiocyanate, industrial grade, powder, coke of Henan province, Hecheng chemical company Limited.

8) Triethanolamine, grade 85, produced by Shanghai-Haojia chemical Co., Ltd; triisopropanolamine, grade 85, produced by Nanjing Red Baoli group; tetrahydroxyethyl ethylenediamine, 99%, produced by Wuhan Yalong New materials Co.

9)108 glue powder, produced by Hebei Ruizhengte New materials science and technology Limited.

Comparative example 1

The ceramsite a is spherical high-strength light artificial ceramsite with the particle size of 5-10mm, the water absorption rate of 24 hours is 11.2 percent, and the bulk density is 720kg/m³The barrel pressure strength was 5.3 MPa.

Spraying water on ceramsite a for moistening, controlling the water-cement ratio to be 0.325, adding 52.5-grade sulphoaluminate cement, a first water reducing agent (the mixing amount of the polycarboxylic acid water reducing agent is 0.20 percent of the using amount of the cement) and a first water retention thickening agent HPMC (the mixing amount is 0.002 percent of the mass of the cement), preparing self-leveling cement slurry with excellent water retention (GB 50119-2013 for reference, the fluidity of the cement slurry is 280mm), pouring the self-leveling cement slurry into a stirrer container, stirring for 240s, separating out the ceramsite through a 5mm slot, naturally drying, enabling the thickness of a cement layer coated on the surface of the ceramsite to be 2mm, and carrying out moisture retention and maintenance for 28 days to obtain ceramsite D1.

Comparative example 2

The ceramsite b is spherical high-strength light artificial ceramsite with the size fraction of 5-10mm, the 24-hour water absorption rate is 9.8 percent, and the bulk density is 800kg/m³The barrel pressure strength was 6.2 MPa.

Ceramsite D2 was prepared by replacing ceramsite a with ceramsite b as described in comparative example 1.

Comparative example 3

The ceramsite c is spherical high-strength light artificial ceramsite with the size fraction of 5-10mm, the 24-hour water absorption rate is 8.2 percent, and the bulk density is 920kg/m³The barrel pressure strength was 8.0 MPa.

Ceramsite D3 was prepared by replacing ceramsite a with ceramsite c in the manner described in comparative example 1.

Comparative example 4

The ceramsite a is spherical high-strength light artificial ceramsite with the particle size of 5-10mm, the water absorption rate of 24 hours is 11.2 percent, and the bulk density is 720kg/m³The barrel pressure strength was 5.3 MPa.

Spraying water to wet the ceramsite a in advance. According to the proportion that 108 kg of rubber powder is dissolved in 100kg of water, stirring, mixing and dissolving to prepare a rubber powder aqueous solution; the water-cement ratio is controlled to be 0.325, 52.5-grade ordinary portland cement, a first water reducing agent (a polycarboxylic acid water reducing agent, the mixing amount is 0.20 percent of the cement using amount) and HPMC (the mixing amount is 0.005 percent of the cement mass) are added to prepare self-leveling cement slurry (refer to GB50119-2013, the fluidity of the cement clean slurry is 280 mm). And then pouring the wetted ceramsite a into a treatment container, stirring for 240s, separating out the ceramsite through a 5mm grate gap, naturally drying, wherein the thickness of a cement layer coated on the surface of the ceramsite is 2mm, and preserving moisture and maintaining for 28D to obtain the ceramsite D4.

Comparative example 5

Ceramsite D5 was prepared by replacing ceramsite a with ceramsite b as described in comparative example 4.

Comparative example 6

Ceramsite D6 was prepared by replacing ceramsite a with ceramsite c in the manner described in comparative example 4.

Comparative example 7

The ceramsite a is spherical high-strength light artificial ceramsite with the particle size of 5-10mm, the water absorption rate of 24 hours is 11.2 percent, and the bulk density is 720kg/m³The barrel pressure strength was 5.3 MPa.

According to the proportion that 108 kg of rubber powder is dissolved in 100kg of water, stirring, mixing and dissolving to prepare a rubber powder aqueous solution; the water-cement ratio is controlled to be 0.325, 52.5-grade ordinary portland cement, a first water reducing agent (a polycarboxylic acid water reducing agent, the mixing amount is 0.20 percent of the cement using amount) and HPMC (the mixing amount is 0.005 percent of the cement mass) are added to prepare self-leveling cement slurry (refer to GB50119-2013, the fluidity of the cement clean slurry is 280 mm). And then pouring the ceramsite a into a treatment container, stirring for 240s, separating out the ceramsite through a 5mm grate gap, naturally drying, wherein the thickness of a cement layer coated on the surface of the ceramsite is 2mm, and preserving moisture and maintaining for 28D to obtain the ceramsite D7.

Comparative example 8

Ceramsite D8 was prepared by replacing ceramsite a with ceramsite b as described in comparative example 4.

Comparative example 9

Ceramsite D9 was prepared by replacing ceramsite a with ceramsite c in the manner described in comparative example 4.

Example 1

The ceramsite a is selected and pretreated according to the following steps:

1) handle 1m³Placing the ceramsite into a container with the diameter of 2m³Vacuumizing the processing container with the volume under the vacuum degree of 0.4MPa for 25min by using an air pump;

2) according to the proportion that 108 kg of rubber powder is dissolved in 100kg of water, stirring, mixing and dissolving to prepare a rubber powder aqueous solution; controlling the water-cement ratio to be 0.325, adding 52.5-grade ordinary portland cement, a first water reducing agent (polycarboxylic acid water reducing agent, the mixing amount is 0.20 percent of the cement amount) and HPMC (the mixing amount is 0.005 percent of the cement mass), and preparing self-leveling cement slurry (GB 50119-2013, the cement neat slurry fluidity is 280mm) with the thickness of 0.4m³And injecting the mixture into the treatment container, stirring for 240S under the condition of keeping the vacuum degree at 0.4MPa, fully absorbing the cement slurry by the ceramsite, separating the ceramsite through a 5mm grate gap, naturally drying, keeping the thickness of a cement layer coated on the surface of the ceramsite to be 2mm, and preserving moisture for 28d to obtain the ceramsite S1. The cement paste can be quickly hardened under air drying to block gaps inside and on the surface of the ceramsite, and the 108 glue can promote the interface bonding strength of the cement and the ceramsite matrix.

Example 2

The ceramsite b is selected and pretreated according to the steps described in the embodiment 1, so that the ceramsite S2 is prepared.

Example 3

The ceramsite c is selected and pretreated according to the steps described in the embodiment 1, so that the ceramsite S3 is prepared.

Testing the cylinder pressure strength and the water absorption of the ceramsite according to GB/T1743.1-2010 and GB/T1743.2-2010 light aggregate and test method thereof, wherein the test results are shown in Table 1; the tensile bonding strength of the cement paste for the 14-day pretreatment and the compactness of the cement paste are tested according to JGJ/T70-2009 Standard test method for basic performance of building mortar, and the test results are shown in Table 2.

TABLE 1 comparison of ceramsite properties

As shown in Table 1, the pretreatment method of the present invention can effectively improve the cylinder pressure strength of the ceramsite and reduce the water absorption.

TABLE 2 Cement mortar Properties for pretreating porcelain granules

As can be seen from Table 2, the cement paste of the examples is superior in cohesive strength and denseness to the cement paste of the comparative examples.

In the following examples, composite reinforcing agents having the compositions in mass percent shown in Table 3 were used, wherein

The defoaming agent 1 is a mixture of tributyl phosphate, PD360 and PD352-C in a mass ratio of 1:1: 1;

the defoaming agent 2 is a mixture of tributyl phosphate, PD360 and PD352-C in a mass ratio of 1:1.5: 1.5;

the defoaming agent 3 is a mixture of tributyl phosphate, PD360 and PD352-C in a mass ratio of 1:2: 2;

the second water-retaining thickening agent 1 is a mixture of CMC, sodium alginate and starch ether in a mass ratio of 1:1: 1;

the second water-retaining thickening agent 2 is a mixture of CMC, sodium alginate and starch ether with the mass ratio of 1:1.2: 1.2;

the second water-retaining thickening agent 3 is a mixture of CMC, sodium alginate and starch ether with the mass ratio of 1:1.5: 1.5;

the cement reinforcing agent 1 is a mixture of sodium thiocyanate, THEED, TEA and TIPA in a mass ratio of 1:1:1: 1;

the cement reinforcing agent 2 is a mixture of sodium thiocyanate, THEED, TEA and TIPA in a mass ratio of 1:1.2:1.5: 1.5;

the cement reinforcing agent 3 is a mixture of sodium thiocyanate, THEED, TEA and TIPA in a mass ratio of 1:1.5:2: 2;

the carrier is slag micropowder.

TABLE 3 example formulation of pervious concrete reinforcing agent

Examples

Preparing pervious concrete

The ceramsite S2 obtained in example 2 is used as a coarse aggregate, and the pervious concrete is prepared according to the mixing ratio shown in Table 4: and (3) adding water, cement, ceramsite and reinforcing agent, controlling the mixing amount of the second water reducing agent, stirring for 240 seconds, and controlling the slump of the discharged concrete to be 30-50mm to obtain the pervious concrete described in examples 41-43, 51-53, 61-63, 71-73 and 81-83.

Comparative examples 4 to 6

Preparing comparative example pervious concrete

Soaking ceramsite b serving as a coarse aggregate for 24h, taking out, draining, and preparing pervious concrete according to the mixing ratio shown in the table 4 until no free water is visible on the surface of the ceramsite: and (3) adding water, cement, ceramsite and reinforcing agent, controlling the mixing amount of the second water reducing agent, stirring for 240 seconds, and controlling the slump of the discharged concrete to be 30-50mm to obtain the pervious concrete as described in comparative examples 4-6.

Comparative examples 7 to 9

Preparing comparative example pervious concrete

Taking ceramsite D2 as coarse aggregate, preparing the pervious concrete according to the mixing ratio shown in Table 4: and (3) adding water, cement, ceramsite and reinforcing agent, controlling the mixing amount of the second water reducing agent, stirring for 240 seconds, and controlling the slump of the discharged concrete to be 30-50mm to obtain the pervious concrete as described in the comparative examples 7-9.

TABLE 4 compounding ratio/kg/m of comparative examples and examples³

Note: as mentioned above, the polycarboxylate superplasticizer and the reinforcing agent are both in the folded-solid mixing amount.

The porosity, the 28d compressive strength and the 28d bending and pulling strength of the ceramsite pervious concrete are tested according to CJJ/T135-2009 technical Specification for pervious cement concrete pavements, and the abrasive resistance test of the pervious concrete is in accordance with the regulations of the existing national standard GB/T12988-2009 test method for the abrasive resistance of inorganic ground materials. The results are shown in Table 5.

TABLE 5 test results of comparative and example

	Void fraction/%)	Abrasion resistance (pit length)/mm	28d compressive strength/MPa	28d tensile Strength/MPa
					Comparative example 4	17.3	31	25.6	2.6
Comparative example 5	16.8	33	23.4	2.8
					Comparative example 6	16.3	34	22.8	2.8
Comparative example 7	16.2	28	27.9	2.8
					Comparative example 8	15.8	27	28.4	2.8
Comparative example 9	15.6	27	28.2	2.9
					EXAMPLE 41	14.7	24	32.9	3.3
Example 42	14.9	24	32.4	3.2
					Example 43	14.5	23	32.7	3.4
Example 51	14.3	24	32.8	3.4
					Example 52	14.8	23	33.1	3.3
Example 53	14.5	24	33.4	3.3
					Example 61	14.6	24	32.6	3.3
Example 62	14.2	23	33.4	3.2
					Practice ofExample 63	14.4	24	33.1	3.2
Example 71	14.8	24	33.8	3.4
					Example 72	14.5	23	33.2	3.3
Example 73	14.6	24	34.1	3.3
					Example 81	14.1	24	33.4	3.5
Example 82	14.6	24	33.1	3.4
					Example 83	14.4	23	33.6	3.3

In table 5, the larger the value of the pit length, the worse the wear resistance. As can be seen from Table 5, compared with the comparative example, the pervious concrete obtained in the embodiment of the invention can effectively improve the compressive strength and the bending strength (the 28d strength can reach more than 32.0MPa and the bending strength can reach more than 3.0MPa through a conventional preparation method), improve the wear resistance, and further improve the anti-stripping performance of the ceramsite in the pervious concrete.

The construction of the pervious concrete mainly comprises the working procedures of paving, forming, surface treatment, seam treatment and the like. The paving can be carried out by adopting a mechanical or manual method; the forming can be carried out by adopting a flat vibrator, a vibration leveling roller, a manual push-pull roller, a vibration leveling beam and the like; the surface treatment is mainly to ensure that the surface appearance is improved, and the surface of the formed pervious concrete is trimmed or cleaned; the arrangement of the joints of the pervious concrete pavement is basically the same as that of common concrete, the contraction joints are arranged at equal intervals, and the distance between the contraction joints is not more than 6 m. And after the pervious concrete is constructed, covering maintenance is adopted, and watering, moisturizing and maintaining are carried out for at least 7 days.

If the pervious concrete surface layer needs to have the effect of exposing the aggregate, a layer of weak acid (such as tartaric acid, gluconic acid and the like) can be sprayed on the conventionally formed concrete surface layer before the concrete is finally set, and after the concrete on the lower layer is finally set, the surface of the concrete is sprayed by a water gun, so that the effect of exposing the ceramsite aggregate pervious concrete can be achieved. If colored ceramsite pervious concrete is required, the required inorganic pigment (5-20) kg/m is added only when the ceramsite concrete is stirred³That is, the description is omitted here.

Compared with the defects and the shortcomings of the existing broken stone pervious concrete technology, the invention has the following beneficial effects:

(1) the ceramsite water permeable concrete has the remarkable characteristics of light weight, high strength, water permeability, water absorption, air permeability and regular and beautiful surface layer.

(2) The ceramsite water-permeable concrete has the characteristics of water purification and gas purification, and can be widely applied to municipal fields such as squares, sidewalks, roads in parks, parking lots and the like.

(3) The preparation material of the ceramsite porous concrete has wide sources, is cheap and easy to obtain, has a simple preparation process, and is suitable for industrial production.

The above description is only for facilitating the understanding of the technical solutions of the present invention by those skilled in the art, and is not intended to limit the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (6)

1. A method for treating ceramsite for concrete is characterized by comprising the following steps:

1) the water absorption rate of 24h is 8 to 12 percent, and the bulk density is 600 to 1000kg/m³1m with the cylinder pressure intensity of 4.0-8.0MPa³Placing the ceramsite into a treatment container, and vacuumizing for 10-30min under the vacuum degree of 0.2-0.5 MPa;

2) stirring, mixing and dissolving 108 kg of rubber powder in 100kg of water according to the proportion of 0.5-1.0kg of the rubber powder to prepare latex aqueous solution; controlling the water cement ratio to be 0.30-0.35, adding 52.5-grade ordinary portland cement, a first water reducing agent and a first water-retaining thickener to prepare self-leveling cement paste with the thickness of 0.3-0.5m³Injecting the mixture into the treatment container, stirring for 180-240s under the condition of keeping the vacuum degree of 0.2-0.5MPa, naturally drying after separating out the ceramsite, wherein the thickness of a cement layer coated on the surface of the ceramsite is 2-3mm, and keeping moisture for 28d for later use, wherein the self-leveling slurry refers to the GB50119-2013 standard, and the fluidity of the cement neat paste is 250-300 mm.

2. The treatment method of claim 1, wherein the first water reducing agent is a polycarboxylic acid liquid water reducing agent with a solid content of 8% -12%, and the mixing amount is 0.13% -0.24% of the using amount of the 52.5-grade ordinary portland cement; the first water-retaining thickener is powder methyl cellulose ether or hydroxypropyl methyl cellulose ether, and the dosage of the first water-retaining thickener is 0.002% -0.008% of the dosage of 52.5-grade ordinary portland cement.

3. Pervious concrete using as coarse aggregate the ceramsite obtained by the method of claim 1 or 2.

4. The pervious concrete of claim 3, comprising the following components in parts by mass:

100-130 parts of water, 350-450 parts of cement, 500-900 parts of coarse aggregate and 15-25 parts of composite reinforcing agent, wherein:

the cement is ordinary 42.5 or 52.5-grade portland cement,

the particle size of the coarse aggregate is 5-10 mm;

the composite reinforcing agent comprises the following components in percentage by mass:

20 to 30 percent of latex powder

1 to 2 percent of defoaming agent

3 to 10 percent of second water-retaining thickening agent

5 to 10 percent of cement reinforcing agent

Balance of carrier

The carrier is silica fume and/or slag micro powder;

the mass parts of the composite reinforcing agent are calculated by solid matters contained in the composite reinforcing agent, and the mass percent of the composite reinforcing agent is calculated by solid matters contained in various compositions;

the strength grade of the pervious concrete is C20-C30, and the construction slump is 30-50 mm.

5. The pervious concrete of claim 4,

the latex powder is acrylate copolymer;

the defoaming agent is a mixture of tributyl phosphate, polyether liquid defoaming agent and siloxane liquid defoaming agent in a mass ratio of 1 (1-2) to (1-2);

the second water-retaining thickening agent is a mixture of methyl cellulose ether, sodium alginate and starch ether in a mass ratio of 1 (1-1.5) to 1 (1-1.5);

the cement reinforcing agent is prepared from the following components in percentage by mass of 1: (1-1.5): (1-2): (1-2) a mixture of sodium thiocyanate, tetrahydroxyethylethylenediamine, triethanolamine, and triisopropanolamine;

the mass ratio is a mass ratio of solid substances contained in the mixture components.

6. The pervious concrete of claim 5,

the starch ether is carboxymethyl starch and/or guar gum ether.