CN114436591B

CN114436591B - Light recycled concrete and preparation process thereof

Info

Publication number: CN114436591B
Application number: CN202210098382.0A
Authority: CN
Inventors: 徐凡; 张应红; 柏成林
Original assignee: Shenzhen Shenjian Concrete Co ltd
Current assignee: Shenzhen Shenjian Concrete Co ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2022-10-21
Anticipated expiration: 2042-01-27
Also published as: CN114436591A

Abstract

The application relates to the technical field of concrete preparation, and particularly discloses light recycled concrete and a preparation process thereof. The application of the light recycled concrete is mainly prepared from the following raw materials: cement, water, fly ash, fine aggregate, recycled aggregate, an air entraining agent, a water reducing agent, a heat storage agent and polyurethane particles; the preparation process of the light recycled concrete comprises the following steps: (1) mixing material A: mixing and stirring the cement, the fine aggregate, the recycled aggregate and the fly ash uniformly to obtain a mixture A; (2) mixing material B: adding a heat storage agent, polyurethane particles and 1/3-1/2 of water into the mixture A to obtain a mixture B; (3) concrete preparation: and adding the water reducing agent, the air entraining agent and the residual water into the mixture B, and uniformly obtaining the light recycled concrete. The lightweight recycled concrete prepared by the method is small in dry apparent density and strong in heat insulation and preservation capacity.

Description

Light recycled concrete and preparation process thereof

Technical Field

The application relates to the technical field of concrete preparation, in particular to light recycled concrete and a preparation process thereof.

Background

The light aggregate concrete, also called light concrete, is compounded with light coarse aggregate, common sand, cement and water, and has the features of light weight, high strength, shock resistance, impervious, etc. The recycled concrete is produced by using construction waste after being cleaned, crushed and screened as concrete aggregate to partially or completely replace natural aggregate.

The light regenerated concrete is prepared by adding light coarse aggregate, common sand, cement and water into crushed, cleaned and screened waste concrete blocks to partially or completely replace natural aggregate such as sand stone and the like.

At present, the light recycled concrete has the problem of poor stability of concrete bubbles, and the bubbles are easy to break before the concrete is transported, so that the heat insulation performance of the light recycled concrete is poor.

Disclosure of Invention

In order to improve the heat insulation performance of the light recycled concrete, the application provides the light recycled concrete and a preparation process thereof.

In a first aspect, the present application provides a light recycled concrete, which adopts the following technical scheme:

the light recycled concrete is mainly prepared from the following raw materials in parts by weight: 300-400 parts of cement, 100-200 parts of water, 20-30 parts of fly ash, 1000-1100 parts of fine aggregate, 100-200 parts of recycled aggregate, 3-5 parts of air-entraining agent, 5-10 parts of water reducing agent, 20-50 parts of heat storage agent and 5-8 parts of polyurethane particles, wherein the heat storage agent mainly comprises ternary molten salt, paraffin, EPS particles and vitrified micro bubbles in the weight ratio of (2-5) to (4-5) to (1-2) to (5-10).

Preferably, the water reducing agent is a polycarboxylic acid water reducing agent.

Preferably, the cement is P42.5 portland cement.

Preferably, the air entraining agent is sodium lignosulfonate.

Preferably, the particle size of the fly ash is 10-25mm.

Preferably, the fine aggregate is natural river sand, is in continuous gradation, has a fineness modulus of 2.9 and a mud content of 0.4wt%.

Preferably, the recycled aggregate is waste concrete.

Preferably, the ternary molten salt is prepared from the following raw materials in percentage by weight: 53 percent of potassium nitrate, 40 percent of sodium nitrite and 7 percent of sodium nitrate.

Preferably, the particle size of the vitrified micro bubbles is 0.5 to 1.6mm.

Preferably, the method for producing the heat storage agent includes the steps of: and (3) uniformly mixing and stirring the ternary molten salt, the paraffin, the EPS particles and the vitrified micro bubbles to obtain the heat storage agent.

By adopting the technical scheme, the addition of the heat storage agent is convenient for improving the heat insulation and heat preservation capability of the light recycled concrete, the fly ash is used for increasing the fluidity of the raw material of the light recycled concrete, and the arrangement condition of the heat storage agent in the light recycled concrete is convenient to optimize; the ternary fused salt in the heat storage agent has strong heat preservation capability and small temperature change range, and can form a phase change layer structure in the light recycled concrete, so that heat transfer is hindered, the heat preservation and heat insulation capability of the light recycled concrete is further improved, the phase change temperature of paraffin is lower, and the paraffin has heat storage capability and is cooperated with the ternary fused salt, so that the situation that the heat storage temperature of the light recycled concrete is too high is reduced; the paraffin, the ternary molten salt, the EPS particles and the vitrified micro bubbles are cooperatively distributed in the light recycled concrete uniformly, so that the heat preservation and insulation capacity of the light recycled concrete is improved.

Preferably, the mass ratio of the heat storage agent to the fly ash to the polyurethane particles is (30-40): (23-28): (6-7).

By adopting the technical scheme, the proportion among the heat storage agent, the fly ash and the polyurethane particles is optimized, so that the mass ratio of the heat storage agent to the fly ash to the polyurethane particles is optimal, the heat insulation function of the light recycled concrete is further improved, the fly ash can increase the fluidity of the light recycled concrete, the distribution condition of the heat storage agent and the polyurethane particles in the light recycled concrete is improved, the heat insulation performance of the prepared light recycled concrete is further improved, and meanwhile, the fly ash is of a porous cellular structure, so that the heat insulation effect of the light recycled concrete is further improved.

Preferably, the EPS particles are modified EPS particles, and the modified EPS particles take the EPS particles as cores and metakaolin as shells.

Preferably, the preparation method of the modified EPS particles comprises the following steps: spraying a surface modifier on the surface of EPS particles, continuously stirring to uniformly wet the surface of the particles to obtain EPS particles with wet surfaces, adding metakaolin, continuously stirring, uniformly mixing to coat a layer of mixture of the surface modifier and the metakaolin on the EPS particles, and then putting the EPS particles into a constant-temperature drying box to dry for 24 hours to obtain modified EPS particles; the surface modifier consists of emulsion powder emulsion and triethanolamine according to the volume ratio of 1:1, the solid content of the emulsion powder emulsion is 40 percent, the volume fraction of the surfactant is 3 percent of the volume fraction of the EPS particles, and the wrapping amount of the metakaolin is 5 times of the mass of the EPS particles.

Preferably, the particle size of the EPS particles is from 2 to 5mm.

Preferably, the metakaolin has a particle size of 0.047-0.049mm.

Preferably, the model of the constant-temperature drying oven is 81M/102-1-A.

By adopting the technical scheme, the metakaolin is wrapped outside the EPS particles, so that the dispersity of the EPS particles in the light recycled concrete is improved conveniently, the affinity of the EPS particles and cement is improved, the interface bonding strength is improved, the compatibility among the raw materials of each component of the light recycled concrete is improved, the dispersion degree of the heat storage agent in the light recycled concrete is improved, the heat conductivity coefficient of the light recycled concrete is reduced, and the compressive strength of the light recycled concrete is improved.

Preferably, the particle size of the recycled aggregate is 10-20mm.

By adopting the technical scheme, when the particle size of the recycled aggregate is smaller, more dust can cover the surface of the recycled aggregate, the bonding strength of the recycled aggregate and cement is influenced, when the particle size is too large, the recycled aggregate has a larger defect, so that the strength of the recycled aggregate is reduced, the strength of the prepared light recycled concrete is influenced, when the particle size of the recycled aggregate is 10-20mm, the recycled aggregate is used as a support to play a compression-resistant role, and meanwhile, the relative amount of cement adhered to the surface of the recycled aggregate is more, so that the strength of the light recycled concrete is improved.

Preferably, the fine aggregate is composed of aluminum powder, barite powder and medium sand according to the mass ratio of (5-10) to (10-20) to (40-50).

Preferably, the aluminum powder has a particle size of 5 to 20 μm.

Preferably, the barite powder has a particle size of 1-3mm.

By adopting the technical scheme, the aluminum powder can react with calcium hydroxide generated by hydration to generate hydrogen bubbles, so that a plurality of honeycomb structures are formed inside the light recycled concrete, the dry apparent density and the heat conductivity coefficient of the light recycled concrete are reduced, and the self weight of the light recycled concrete is further reduced; the addition of barite powder is convenient for improving the early strength of the light recycled concrete and simultaneously inhibiting the later strength from shrinking; the medium sand is cooperated with the barite powder and the aluminum powder, so that the workability among the components of the light recycled concrete is improved, and the compressive strength of the light recycled concrete is further improved.

Preferably, the water reducing agent is mainly prepared from the following raw materials in parts by weight: 1-2 parts of acrylic resin, 5-10 parts of polymethyl acrylate, 1-2 parts of sodium carboxymethyl cellulose, 1-2 parts of Arabic gum and 2-3 parts of sodium dodecyl sulfate.

By adopting the technical scheme, the water reducing agent is obtained by compounding various raw materials, so that the fluidity of the raw material mixture of the light recycled concrete is convenient to improve, the water consumption is reduced, in addition, the compressive strength and the flexural strength of the light recycled concrete can be improved, the cracking condition of the light recycled concrete is reduced, and meanwhile, the water reducing agent obtained by compounding various components has strong plasticizing and air entraining functions, so that the dry apparent density of the light recycled concrete is convenient to reduce.

Preferably, the particle size of the polyurethane particles is 3-5mm.

By adopting the technical scheme, when the particle size of the polyurethane particles is 3-5mm, the cost is lower, meanwhile, the compressive strength of the light recycled concrete is not influenced, and the polyurethane particles can be conveniently and uniformly dispersed in the light recycled concrete, so that the heat insulation performance of the light recycled concrete is further improved.

Preferably, the polyurethane particles are modified polyurethane particles, and the modification method of the modified polyurethane particles comprises the following steps: and (3) carrying out atomization waterproof treatment on the polyurethane particles, and wrapping the polyurethane particles by using slag portland cement and a flame retardant to obtain the polyurethane flame retardant.

Preferably, the preparation method of the modified polyurethane particle comprises the following steps: carrying out atomization waterproof treatment on polyurethane particles by using a liquid organosilicon waterproof agent, adding slag portland cement and a flame retardant to wrap the surfaces of the polyurethane particles after the surfaces of the polyurethane particles are completely wetted, and drying the wrapped polyurethane particles in an oven at the temperature of 105 ℃ for 2h to obtain modified polyurethane particles; wherein the mass ratio of the liquid organosilicon waterproofing agent to the slag portland cement to the flame retardant to the polyurethane particles is 15.

Preferably, the flame retardant is magnesium hydroxide.

Through adopting above-mentioned technical scheme, polyurethane is through fire retardant, cement modification back, and heat preservation and heat-proof quality preferred, the fire behavior preferred simultaneously, weight is lighter, is convenient for reduce the dry apparent density of light recycled concrete, can mix with cement better behind the polyurethane parcel slag portland cement, and the compatibility is better to be convenient for strengthen light recycled concrete compressive strength, improve the heat-proof quality of light recycled concrete.

Preferably, 1-2 parts by weight of glass fiber is also added into the raw materials.

Preferably, the glass fibers have a particle size of 3mm to 6mm.

Through adopting above-mentioned technical scheme, glass fiber distributes in light recycled concrete, can play the effect of strengthening rib to improve light recycled concrete's compressive strength, the addition of glass fiber makes the inside space of light recycled concrete increase simultaneously, thereby reduces light recycled concrete's dry apparent density, and then reduces light recycled concrete's coefficient of heat conductivity.

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

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

(1) Mixing material A: mixing and stirring the cement, the fine aggregate, the recycled aggregate and the fly ash uniformly to obtain a mixture A;

(2) And (3) mixing material B: adding a heat storage agent, polyurethane particles and 1/3-1/2 of water into the mixture A prepared in the step (1), and performing ultrasonic mixing uniformly to obtain a mixture B; if the glass fiber needs to be added, adding the glass fiber in the current step;

(3) Preparing concrete: and adding the water reducing agent, the air entraining agent and the residual water into the mixture B, ultrasonically mixing, and homogenizing uniformly to obtain the light recycled concrete.

Preferably, the temperature in the step (1) is 25 ℃, and the stirring speed is 260r/min.

Preferably, the temperature in the step (2) is 40-45 ℃, the power of the ultrasonic wave is 350-400w, and the frequency is 25-40Hz.

Preferably, the temperature in the step (3) is 40-45 ℃, the ultrasonic power is 350-400w, the frequency is 25-40Hz, the ultrasonic time is 20-25min, and the homogenizing pressure is 25-40MPa.

By adopting the technical scheme, the cement, the fine aggregate, the recycled aggregate and the fly ash are stirred under the anhydrous condition, the materials are high in fluidity and easy to stir uniformly, then the heat storage agent, the polyurethane particles and part of water are added into the mixture A, and the mixture B is obtained under the action of ultrasound, so that the components of the mixture B are better in compatibility, the air entraining agent and the water reducing agent are added to further improve the dispersibility of the materials, and meanwhile, the materials of the light recycled concrete are more fully mixed under the action of ultrasound and homogenization, so that the compressive strength of the prepared light recycled concrete is further improved, the dispersion condition of the heat storage agent in the light recycled concrete is optimized, and the heat insulation and heat preservation effects of the light recycled concrete are further improved.

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

1. the application of the light recycled concrete is that the heat storage agent is added, and the heat storage agent is more uniformly distributed in the light recycled concrete under the action of the fly ash, so that the heat preservation and insulation capacity of the light recycled concrete is improved.

2. The heat storage agent in the light recycled concrete is compounded through multiple components, and the paraffin and the ternary fused salt are matched with each other, so that the heat insulation and heat preservation capacity of the light recycled concrete is improved.

3. According to the light recycled concrete, the raw materials of the light recycled concrete are mixed in batches, so that the compatibility and the dispersity among all the components of the light recycled concrete are improved conveniently, the compressive strength of the light recycled concrete is improved, and the dry apparent density and the heat conductivity coefficient of the light recycled concrete are reduced.

Detailed Description

The present application will be described in further detail with reference to examples.

Optionally, the ternary molten salt manufacturer is Shanxi Jinlan chemical industry Co.

Optionally, the manufacturer of the polyurethane particles is environment-friendly science and technology limited, chaofang Danchen.

Optionally, the particle size of the fly ash is 10-25mm.

Optionally, the EPS particles, also called polystyrene particles, are produced by Blackhorse plastics Co., ltd, dongguan.

Optionally, the particle size of the vitrified micro bubbles is 0.5-1.6mm.

Examples

Example 1

The light recycled concrete of the embodiment is prepared from the following raw materials by weight: 300kg of cement, 100kg of water, 20kg of fly ash, 1000kg of fine aggregate, 100kg of recycled aggregate, 3kg of air entraining agent, 5kg of water reducing agent, 20kg of heat storage agent and 5kg of polyurethane particles, wherein the heat storage agent consists of ternary molten salt, paraffin, EPS particles and vitrified micro-beads according to a weight ratio of 2; the cement is P42.5 ordinary portland cement; the air entraining agent is sodium lignosulfonate; the average grain diameter of the fly ash is 15mm; the fine aggregate is natural river sand, is in continuous gradation, has the fineness modulus of 2.9 and the mud content of 0.4wt%; the recycled aggregate is waste concrete, and the average particle size of the recycled aggregate is 15mm; the ternary molten salt is prepared from the following raw materials in percentage by weight: 53% of potassium nitrate, 40% of sodium nitrite and 7% of sodium nitrate; the average grain diameter of the vitrified micro bubbles is 1mm; the average particle size of the EPS particles is 3mm; the average particle size of the polyurethane particles is 4mm; the preparation method of the heat storage agent comprises the following steps: and (3) uniformly mixing and stirring the ternary molten salt, the paraffin, the EPS particles and the vitrified micro bubbles to obtain the heat storage agent.

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

(1) Mixing material A: mixing and stirring the cement, the fine aggregate, the recycled aggregate and the fly ash uniformly at the temperature of 25 ℃ and the stirring speed of 260r/min to obtain a mixture A;

(2) And (3) mixing material B: adding a heat storage agent, polyurethane particles and 1/2 of water into the mixture A prepared in the step (2), and uniformly mixing by using ultrasonic waves to obtain a mixture B, wherein the ultrasonic temperature is 45 ℃, the ultrasonic power is 400w, and the frequency is 40Hz;

(3) Preparing concrete: and adding the water reducing agent, the air entraining agent and the residual water into the mixture B, ultrasonically mixing, and uniformly homogenizing to obtain the light recycled concrete, wherein the ultrasonic temperature is 45 ℃, the ultrasonic power is 400w, the frequency is 40Hz, the ultrasonic time is 25min, and the homogenizing pressure is 40MPa.

Examples 2 to 5

Examples 2 to 5 each provide light recycled concrete having different raw material component ratios, and the components of the light recycled concrete for each example are shown in table 1, and the unit of the raw material ratio is kg.

TABLE 1 proportioning of the components of the light recycled concrete prepared in examples 1-5

Raw materials	Example 1	Example 2	Example 3	Example 4	Example 5
						Cement	300	350	400	350	350
Water (W)	100	150	200	150	150
						Fly ash	20	23	30	25	28
Fine aggregate	1000	1050	1100	1050	1050
						Recycled aggregate	100	150	200	150	150
Air entraining agent	3	4	5	4	4
						Water reducing agent	5	7	8	7	7
Heat storage agent	20	30	50	35	40
						Polyurethane particles	5	6	8	6.5	7

The lightweight recycled concrete of examples 2 to 5 is different from that of example 1 in that: the components of the light recycled concrete have different proportions, and the rest is completely the same as the embodiment 1.

The preparation process of the lightweight recycled concrete of examples 2 to 5 was exactly the same as that of example 1.

Example 6

This embodiment is different from embodiment 4 in that: the heat storage agent consists of ternary molten salt, paraffin, EPS particles and vitrified micro bubbles according to a mass ratio of 5.

The preparation process of the lightweight recycled concrete of this example is exactly the same as that of example 4.

Example 7

This embodiment is different from embodiment 4 in that: the EPS particles are modified EPS particles, and the preparation method of the modified EPS particles comprises the following steps: spraying a surface modifier on the surface of EPS particles, continuously stirring to uniformly wet the surface of the particles to obtain EPS particles with wet surfaces, adding metakaolin, continuously stirring, uniformly mixing to coat a layer of mixture of the surface modifier and the metakaolin on the EPS particles, and then putting the EPS particles into a constant-temperature drying box to dry for 24 hours to obtain modified EPS particles; the surface modifier consists of emulsion powder emulsion and triethanolamine according to the volume ratio of 1:1, the solid content of the emulsion powder emulsion is 40 percent, the volume fraction of the surfactant is 3 percent of the volume fraction of the EPS particles, and the wrapping amount of the metakaolin is 5 times of the mass of the EPS particles; wherein the average particle diameter of the metakaolin is 0.047mm, and the model of the constant-temperature drying oven is 81M/102-1-A. The rest is exactly the same as in example 4.

Example 8

This embodiment is different from embodiment 4 in that: the fine aggregate is composed of aluminum powder, barite powder and medium sand according to the mass ratio of 8.

Example 9

This embodiment is different from embodiment 4 in that: the water reducing agent is prepared from the following raw materials in parts by weight: 1kg of acrylic resin, 5kg of polymethyl acrylate, 1kg of sodium carboxymethylcellulose, 1kg of Arabic gum and 2kg of sodium dodecyl sulfate, and the preparation method of the water reducing agent comprises the following steps: mixing acrylic resin, polymethyl acrylate, sodium carboxymethylcellulose, arabic gum and sodium dodecyl sulfate, and stirring uniformly to obtain the water reducer; the rest is exactly the same as in example 4.

Example 10

This embodiment is different from embodiment 4 in that: the preparation method of the modified polyurethane particle comprises the following steps: carrying out atomization waterproof treatment on polyurethane particles by using a liquid organosilicon waterproof agent, adding slag portland cement and magnesium hydroxide for wrapping after the surfaces of the polyurethane particles are completely wetted, and drying the wrapped polyurethane particles in an oven at the temperature of 105 ℃ for 2h to obtain modified polyurethane particles; wherein the mass ratio of the liquid organosilicon waterproofing agent, the P42.5 ordinary portland cement, the flame retardant and the polyurethane particles is 15. The rest is exactly the same as in example 4.

Example 11

This embodiment is different from embodiment 4 in that: also included was 1kg of glass fiber, the other parts being exactly the same as in example 4.

The preparation process of the light recycled concrete of the embodiment is different from that of the embodiment 4 in that: adding a heat storage agent, polyurethane particles, glass fibers and 1/2 of water into the mixture A prepared in the step (1), and uniformly mixing by ultrasonic waves to obtain a mixture B; the rest is exactly the same as in example 4.

Comparative example

Comparative example 1

The light recycled concrete of the comparative example is composed of the following raw materials by weight: 300kg of cement, 100kg of water, 20kg of fly ash, 1000kg of fine aggregate, 100kg of recycled aggregate, 3kg of air-entraining agent, 5kg of water reducing agent and 5kg of polyurethane particles, and the rest is exactly the same as in example 1.

The preparation process of the light recycled concrete of the comparative example comprises the following steps:

(2) And (3) mixing material B: adding polyurethane particles and 1/2 of water into the mixture A prepared in the step (1), and uniformly mixing by using ultrasonic waves to obtain a mixture B, wherein the ultrasonic temperature is 45 ℃, the ultrasonic power is 400w, and the frequency is 40Hz;

Comparative example 2

This comparative example differs from example 1 in that: the heat storage agent was paraffin, and the rest was exactly the same as in example 1.

The process for producing the lightweight recycled concrete of this comparative example was exactly the same as in example 1.

Comparative example 3

This comparative example differs from example 1 in that: the heat storage agent consists of ternary molten salt and paraffin wax according to the mass ratio of 2:3, and the rest is completely the same as that of the embodiment 1.

Comparative example 4

This comparative example differs from example 1 in that: the heat storage agent consists of ternary molten salt, paraffin and EPS particles according to a mass ratio of 2.

Comparative example 5

The lightweight recycled concrete of this comparative example was composed of 200kg of cement, 80kg of water, 5kg of fly ash, 950kg of fine aggregate, 100kg of recycled aggregate, 3kg of an air-entraining agent, 5kg of a water reducing agent, 10kg of a heat storage agent, and 10kg of polyurethane particles, all of which were the same as in example 1.

Comparative example 6

The raw material ratio of each component of the light recycled concrete of the comparative example is completely the same as that of the example 1.

The preparation process of the light recycled concrete of the comparative example comprises the following steps: and ultrasonically mixing and stirring cement, water, fly ash, fine aggregate, recycled aggregate, an air entraining agent, a water reducing agent, a heat storage agent and polyurethane particles uniformly to obtain the material, wherein the ultrasonic temperature is 45 ℃, the ultrasonic power is 400w, and the frequency is 40Hz.

Comparative example 7

The light recycled concrete of the comparative example is composed of the following raw materials by weight: 300kg of cement, 100kg of water, 1000kg of fine aggregate, 100kg of recycled aggregate, 3kg of an air-entraining agent, 5kg of a water reducing agent, 5kg of polyurethane particles and 20kg of a heat storage agent, and the rest is exactly the same as in example 1.

(1) Mixing material A: mixing and stirring the cement, the fine aggregate and the recycled aggregate uniformly at the temperature of 25 ℃ and the stirring speed of 260r/min to obtain a mixture A;

(2) And (3) mixing material B: adding polyurethane particles, a heat storage agent and 1/2 of water into the mixture A prepared in the step (1), and uniformly mixing by using ultrasonic waves to obtain a mixture B, wherein the ultrasonic temperature is 45 ℃, the ultrasonic power is 400w, and the ultrasonic frequency is 40Hz;

Performance test

Dry apparent density: the dry apparent density of the lightweight recycled concrete obtained in examples 1 to 11 and comparative examples 1 to 7 was measured by the crushing time baking method in JGJ51-2002 "lightweight aggregate concrete technical Specification", and the measurement results are shown in Table 2.

Compressive strength: the lightweight recycled concrete prepared in examples 1 to 11 and comparative examples 1 to 7 was used to prepare test blocks according to the method of GB/T50081-2016 Standard test methods for mechanical Properties of general concrete, and the compressive strength of the standard test blocks cured for 7d and 28d was measured, with the test results shown in Table 2.

And (3) detecting the heat conducting property: the lightweight recycled concrete prepared in examples 1 to 11 and comparative examples 1 to 7 was used to prepare standard test blocks according to the test method of GB/T10294-2008 "testing method for testing thermal insulation material steady-state thermal resistance and related properties using guarded hot plate", and the thermal conductivity of each test sample was measured, and the test results are shown in Table 2.

TABLE 2 Properties of light recycled concrete prepared in examples 1 to 11 and comparative examples 1 to 7

In combination with example 1 and comparative example 1, and table 2, it can be seen that the heat storage agent is added in example 1 compared with comparative example 1, and the addition of the heat storage agent reduces the thermal conductivity of the prepared light recycled concrete, so that the heat insulation and preservation capability of the light recycled concrete is enhanced.

By combining the example 1 and the comparative examples 2 to 4 and combining the table 2, it can be seen that the heat storage agent obtained by compounding a plurality of components is adopted in the light recycled concrete of the example 1, so that the heat storage effect is better, the dry apparent density of the light recycled concrete is reduced, and the compressive strength of the light recycled concrete is improved.

By combining example 1 and comparative example 5, and by combining table 2, it can be seen that the dry apparent density, thermal conductivity and compressive strength of the lightweight recycled concrete are greatly affected by changing the proportion of the components of the lightweight recycled concrete.

By combining example 1 and comparative example 6, and by combining table 2, it can be seen that the raw materials of the light recycled concrete are mixed in batches, so that the mixing uniformity among the components of the raw materials of the light recycled concrete is improved, the dispersibility of the heat storage agent in the light recycled concrete is further improved, the thermal conductivity and the dry apparent density of the light recycled concrete are reduced, and the compressive strength of the light recycled concrete is improved.

By combining the example 1 and the comparative example 7 and table 2, it can be seen that in the example 1, the fly ash and the heat storage agent are cooperatively matched, and the distribution condition of the heat storage agent in the light recycled concrete is improved by the fly ash, so that the heat storage and insulation capacity of the light recycled concrete is improved, and the compressive strength of the light recycled concrete is improved.

By combining the examples 1 to 6 and table 2, it can be seen that the proportions of the components of the raw materials of the light recycled concrete are optimized, so that the proportions of the components are optimized, and the heat insulation performance and the compressive strength of the light recycled concrete are improved.

By combining the example 4 and the examples 7 to 10 and combining the table 2, it can be seen that the EPS particles and the polyurethane particles in the light recycled concrete are modified, so that the compatibility of the EPS particles and the polyurethane particles with other raw materials is improved, the dry apparent density and the thermal conductivity of the light recycled concrete are further reduced, and the compressive strength of the light recycled concrete is improved.

By combining the example 4 and the example 11 and combining the table 2, it can be seen that the addition of the glass fiber is convenient for enhancing the connection toughness among the components of the light recycled concrete, so that the compressive strength of the light recycled concrete is improved, and the cracking of the light recycled concrete is reduced.

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 light recycled concrete is characterized by being mainly prepared from the following raw materials in parts by weight: 300-400 parts of cement, 100-200 parts of water, 20-30 parts of fly ash, 1000-1100 parts of fine aggregate, 100-200 parts of recycled aggregate, 3-5 parts of air entraining agent, 5-10 parts of water reducing agent, 20-30 parts of heat storage agent, 5-8 parts of polyurethane particles and 1-2 parts of glass fiber, wherein the heat storage agent mainly comprises ternary molten salt, paraffin, EPS particles and vitrified micro beads in the weight ratio of (2-5) to (4-5) to (1-2) to (5-10), the EPS particles are modified EPS particles, the modified EPS particles take EPS particles as cores and metakaolin as shells, and the preparation method of the modified EPS particles comprises the following steps: spraying a surface modifier on the surface of EPS particles, continuously stirring to uniformly wet the surface of the particles to obtain EPS particles with wet surfaces, adding metakaolin, continuously stirring, uniformly mixing to coat a layer of mixture of the surface modifier and the metakaolin on the EPS particles, and then putting the EPS particles into a constant-temperature drying box to dry for 24 hours to obtain modified EPS particles; the surface modifier consists of emulsion powder emulsion and triethanolamine according to the volume ratio of 1:1, the solid content of the emulsion powder emulsion is 40 percent, the volume fraction of the surfactant is 3 percent of the volume fraction of EPS particles, the wrapping amount of metakaolin is 5 times of the mass of the EPS particles, the particle size of the EPS particles is 2-5mm, and the particle size of the metakaolin is 0.047-0.049mm; the particle size of the recycled aggregate is 10-20mm.

2. The lightweight recycled concrete of claim 1, wherein: the mass ratio of the heat storage agent, the fly ash and the polyurethane particles is (30-40): (23-28): (6-7).

3. The lightweight recycled concrete according to claim 2, wherein: the fine aggregate is composed of aluminum powder, barite powder and medium sand according to the mass ratio of (5-10) to (10-20) to (40-50).

4. The lightweight recycled concrete according to claim 2, wherein: the water reducing agent is mainly prepared from the following raw materials in parts by weight: 1-2 parts of acrylic resin, 5-10 parts of polymethyl acrylate, 1-2 parts of sodium carboxymethyl cellulose, 1-2 parts of Arabic gum and 2-3 parts of sodium dodecyl sulfate.

5. The lightweight recycled concrete of claim 2, wherein: the particle size of the polyurethane particles is 3-5mm.

6. The lightweight recycled concrete according to claim 5, wherein: the polyurethane particles are modified polyurethane particles, and the modification method of the modified polyurethane particles comprises the following steps: and (3) carrying out atomization waterproof treatment on the polyurethane particles, and wrapping the polyurethane particles by using slag portland cement and a flame retardant to obtain the polyurethane flame retardant.

7. A process for the preparation of a lightweight recycled concrete according to any one of claims 1 to 6, characterized in that: comprises the following steps of (a) preparing a solution,

(2) And (3) mixing material B: adding a heat storage agent, polyurethane particles and 1/3-1/2 of water into the mixture A prepared in the step (1), and uniformly mixing by ultrasonic to obtain a mixture B; glass fibers, added in the current step;