CN112321212B - Heat-preservation light foamed concrete and preparation method thereof - Google Patents

Abstract

The application relates to the technical field of foamed concrete, and particularly discloses heat-insulating light foamed concrete and a preparation method thereof, wherein the heat-insulating light foamed concrete comprises the following components in parts by weight: 60-90 parts of water, 100-200 parts of cement, 3.6-6 parts of foaming agent, 2-4 parts of hydrogenated castor oil, 3-8 parts of waterproof agent and 20-45 parts of heat-insulating light filler, and the preparation method of the heat-insulating light foamed concrete comprises the following steps: step one, preparing a waterproof agent; mixing the waterproof agent, cyclodextrin, hydrogenated castor oil and the residual 1/2 polydopamine solution according to the formula amount, adding a foaming agent for foaming under the constant temperature condition of 50-65 ℃, and preserving heat for 30-50min to prepare slurry; and step three, uniformly stirring and mixing water, cement and the heat-preservation lightweight filler according to the formula amount, adding the slurry, mixing and homogenizing, heating to 70-85 ℃, preserving heat for 4-8 hours, and then demoulding to obtain the foamed concrete. By adopting the raw material components and the specific preparation method, the prepared foamed concrete has good heat insulation performance and good waterproof performance.

Description

Heat-preservation light foamed concrete and preparation method thereof

Technical Field

The application relates to the field of foamed concrete, in particular to heat-insulating light foamed concrete and a preparation method thereof.

Background

The foamed concrete is a novel light heat-insulating material containing a large number of closed air holes, which is formed by fully foaming a foaming agent in a mechanical mode through a foaming system of a foaming machine, uniformly mixing the foam with cement slurry, then carrying out cast-in-place construction or mould forming through a pumping system of the foaming machine and carrying out natural curing.

The foam concrete has good characteristics, is widely applied to energy-saving wall materials, and is also applied in other aspects. At present, the application of foam concrete in China is mainly roof foam concrete heat-insulating layer cast-in-place, foam concrete surface blocks, foam concrete light wall boards and foam concrete compensation foundations.

For example, patent application with publication number CN104446633A discloses a preparation method of foamed concrete, which comprises the following specific steps: weighing the following raw materials in parts by weight: 100 parts of cement; 50-100 parts of water; sodium dodecyl sulfate, 1-2.5 parts; 10-12 parts of protein foaming agent; 2-8 parts of diatom powder; preparing cement paste, weighing cement and water according to the proportion, adding into a stirrer, and uniformly mixing; then adding weighed sodium dodecyl sulfate, and stirring for 3 minutes; adding 1/3 protein foaming agent, stirring at 50 rpm for 1.5-3 min, adding the rest protein foaming agent, and stirring at 80 rpm for 2-3 min; and finally, casting, standing and curing to form a concrete finished product.

In view of the above-mentioned related technologies, the inventors found that the foamed concrete prepared by the above-mentioned method has a general heat-insulating effect and a poor water resistance.

Disclosure of Invention

In order to improve the heat preservation performance and the waterproofness of concrete, the application provides heat preservation lightweight foaming concrete and a preparation method thereof.

In a first aspect, the present application provides a heat-insulating lightweight foamed concrete, which adopts the following technical scheme:

the heat-preservation lightweight foamed concrete comprises the following components in parts by weight: 60-90 parts of water, 100-200 parts of cement, 3.6-6 parts of foaming agent, 2-4 parts of hydrogenated castor oil, 3-8 parts of waterproof agent and 20-45 parts of heat-insulating light filler, wherein the waterproof agent comprises the following components in parts by weight: 1.2-2.5 parts of sodium silicate, 0.8-2 parts of silane coupling agent and 1-3.5 parts of dopamine.

By adopting the technical scheme, the foaming agent has higher surface activity, can effectively reduce the surface tension of liquid, is arranged on the surface of the liquid film by the two electronic layers to surround air to form bubbles, so that the concrete contains a large number of closed air holes, and achieves a certain heat preservation effect. The heat-insulating light filler can improve the heat-insulating property of the concrete and also improve the compressive strength of the concrete; the hydrogenated castor oil has thickening and slow-release functions, can change the fluidity of concrete, can reduce the hydration heat generated in the hydration process of cement, has a slow-release function, and has a reinforcing function in cooperation with the heat-insulating light filler. The waterproof agent can obviously improve the waterproof performance of concrete, so that the concrete has excellent waterproof performance.

Preferably, the foaming agent comprises alkyl glucoside and tetrahydrofurfuryl alcohol, and the mass ratio of the alkyl glucoside to the tetrahydrofurfuryl alcohol is 1 (0.8-2).

By adopting the technical scheme, the alkyl glucoside has high surface activity, high viscosity, rich foam, and is fine and stable; the tetrahydrofurfuryl alcohol has good dispersibility, has a certain stabilizing effect on foam, and can improve the dispersibility of the foam and the whole system, thereby improving the heat-insulating property of concrete. And sodium ions ionized from the sodium silicate can also improve the foam performance of the system, so that the surface activity of the alkyl glucoside is enhanced, the surface tension of the solution is reduced, the electrostatic repulsion between molecules is reduced, the foam stabilizing effect is achieved, meanwhile, weak gel is formed on a gas-liquid interface, and the water resistance of the concrete is improved by the weak gel and other raw material components in the waterproof agent in a synergistic manner.

Preferably, the alkyl glucoside is selected from one of decyl glucoside, dodecyl glucoside or hexadecyl glucoside.

By adopting the technical scheme, the alkyl glucoside has the advantages of common nonionic and anionic surfactants, has good foaming power and stable and fine foam, can form closed pores in concrete, has good compatibility and good compatibility with other components. The specific components of the alkyl glucoside are optimized, and the internal porosity of the product is further improved in a synergistic way with other raw material components, so that the heat preservation performance of the product is improved.

Preferably, the food also comprises cyclodextrin, and the weight part of the cyclodextrin is 1-3 parts.

By adopting the technical scheme, the cyclodextrin is a cyclic oligosaccharide, has a slightly conical hollow cylindrical three-dimensional annular structure, and can play a certain slow release role in concrete; meanwhile, due to the special annular structure, a hydrophobic region is formed in the cavity under the shielding effect of a C-H bond, and various organic compounds can be embedded into the hydrophobic cavity to form a wrapping compound, so that the thermal stability of concrete can be enhanced, and the thermal insulation performance of the concrete can be improved.

Preferably, the heat-preservation lightweight filler comprises the following components in parts by weight: 7-16 parts of perlite, 5-11 parts of wood fiber particles, 5-10 parts of glass bead particles and 3-8 parts of aerogel.

By adopting the technical scheme, perlite, wood fiber particles, glass bead particles and aerogel are used as heat-insulating light fillers and are reasonably compounded, so that the heat-insulating property of the product can be improved by cooperating with cyclodextrin, and the compressive strength of concrete can be improved. The perlite has the advantages of light apparent density, low heat conductivity coefficient, good chemical stability, wide application temperature range, small moisture absorption capacity, no toxicity, no odor, fire resistance and sound absorption, and improves the strength of the concrete while considering the enterprise cost. The wood fiber particles are used as filler to play a reinforcing role, a certain strength support is provided, the aerogel can improve the porosity of the concrete, the density of the concrete is reduced, the heat conduction is further reduced, and the heat insulation performance of the product is improved.

Preferably, the particle size of the wood fiber particles is 40-100 meshes, and the particle size of the glass bead particles is 60-80 meshes.

By adopting the technical scheme, the particle sizes of the wood fiber particles and the glass bead particles are optimized, the heat conductivity coefficient of the concrete is reduced, and the compressive strength of the concrete is improved by cooperating with perlite.

In a second aspect, the application provides a preparation method of the heat-insulating light foamed concrete, which adopts the following technical scheme:

a preparation method of heat-insulating light foaming concrete comprises the following steps:

step one, preparing a waterproof agent;

mixing the waterproof agent, cyclodextrin, hydrogenated castor oil and the residual 1/2 polydopamine solution according to the formula amount, adding a foaming agent for foaming under the constant temperature condition of 50-65 ℃, and preserving heat for 30-50min to prepare slurry;

and step three, uniformly stirring and mixing water, cement and the heat-preservation light filler according to the formula amount, adding the slurry, mixing and homogenizing, heating to 70-85 ℃, preserving heat for 4-8 hours, and then demoulding to obtain the concrete.

By adopting the technical scheme, the formed polydopamine solution is equally divided, the adding sequence of the materials is strictly controlled, so that the components interact with each other, the components have good interaction force under the action of the polydopamine solution to form slurry with certain viscosity, and the slurry is added into a subsequent cementing material to reduce foam collapse in the preparation process and improve the quality of concrete.

Preferably, in the first step, the preparation method of the waterproof agent comprises the following steps:

step 1, taking deionized water with the mass 5 times of that of dopamine, dissolving the dopamine in the deionized water, adjusting the pH value to 8.0-8.5, stirring for 2-3h, and standing for 2-5 days to prepare a polydopamine solution;

and 2, equally dividing the polydopamine solution into 2 parts by mass, adding sodium silicate and a silane coupling agent into one part of the polydopamine solution, and uniformly mixing and stirring to obtain the waterproof agent.

By adopting the technical scheme, dopamine is subjected to auto-polymerization under an alkaline condition to form a bonding liquid containing polydopamine, the polydopamine and a silane coupling agent are reacted after the silane coupling agent is added, and the polydopamine and the silane coupling agent and sodium silicate are cooperated to form a hydrophobic surface, and the hydrophobic surface formed by the silane coupling agent and the polydopamine has good hydrophobicity and stability due to the covalent interaction, so that the waterproof performance of concrete is remarkably improved.

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

1. the foaming agent has higher surface activity, can effectively reduce the surface tension of liquid, and is arranged on the surface of a liquid film by two electron layers to surround air to form bubbles, so that the concrete contains a large number of closed air holes, and a certain heat preservation effect is achieved. The heat-insulating light filler can improve the heat-insulating property of the concrete and also improve the compressive strength of the concrete; the hydrogenated castor oil has thickening and slow-release functions, can change the fluidity of concrete, can reduce hydration heat generated in the hydration process of cement, and has a slow-release function.

2. The raw materials of the concrete slow-release agent are cyclodextrin, and the cyclodextrin is a cyclic oligosaccharide, has a slightly conical hollow cylindrical three-dimensional annular structure and can play a certain slow-release role in concrete; meanwhile, due to the special annular structure, a hydrophobic region is formed in the cavity under the shielding effect of a C-H bond, and various organic compounds can be embedded into the hydrophobic cavity, so that the thermal stability of concrete can be enhanced, and the thermal insulation performance of the concrete can be improved.

3. The water-proofing agent prepared by the selected water-proofing agent components and the specific preparation method enables concrete to form a hydrophobic surface, and the water-proofing performance of the concrete is remarkably improved.

Detailed Description

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

The raw materials selected in the application are common commercial raw materials.

Examples

Example 1

The foamed concrete comprises the following components in parts by weight: the heat-preservation light-weight filler comprises 7 kg of perlite, 5 kg of wood fiber particles, 5 kg of glass bead particles and 3 kg of aerogel, wherein the foaming agent comprises 2 kg of decyl glucoside and 1.6 kg of tetrahydrofurfuryl alcohol, and the hydrogenated castor oil comprises 2 kg of hydrogenated castor oil, the water-proofing agent comprises 1.2 kg of sodium silicate, 0.8 kg of silane coupling agent and 1 kg of dopamine; wherein the grain diameter of the wood fiber is 60-80 meshes, and the grain diameter of the glass bead grains is 60-70 meshes;

the preparation method of the foamed concrete comprises the following steps:

step one, preparing a waterproof agent;

the preparation method of the waterproof agent comprises the following steps:

step 1, taking deionized water with the mass 5 times of that of dopamine, dissolving the dopamine in the deionized water, adjusting the pH value to 8.0, stirring for 2.5 hours, and standing for 4 hours to prepare a polydopamine solution;

and 2, equally dividing the polydopamine solution into 2 kg of the polydopamine solution according to the quality, adding the sodium silicate and the silane coupling agent into one kg of the polydopamine solution, and mixing and stirring uniformly to obtain the waterproof agent.

Mixing the waterproof agent, the cyclodextrin, the hydrogenated castor oil and the rest one kg of polydopamine solution according to the formula amount, adding a foaming agent for foaming under the constant temperature condition of 55 ℃, and preserving heat for 40min to obtain slurry;

and step three, uniformly stirring and mixing water, cement and the heat-preservation lightweight filler, adding the slurry, mixing and homogenizing, heating to 80 ℃, preserving heat for 5 hours, and then demolding to obtain the foamed concrete.

Examples 2 to 12 differ from example 1 only in the composition of the starting materials and are otherwise the same as in example 1; the respective raw material components in examples 1 to 7 are shown in Table 1, and the respective raw material components in examples 8 to 12 are shown in Table 2.

Table 1 examples 1-7 each raw material composition

Table 2 examples 8-12 raw material compositions

Comparative example

Comparative example 1

The difference from example 1 is that no hydrogenated castor oil is added, and the rest is the same as example 1.

Comparative example 2

The difference from example 1 is that the foaming agent is sodium dodecylbenzenesulfonate, and the rest is the same as example 1.

Comparative example 3

The difference from example 1 is that the same as example 1 was used without adding dopamine.

Comparative example 4

The difference from example 1 is that the preparation method of the foamed concrete comprises the following steps:

step one, preparing a waterproof agent;

the preparation method of the waterproof agent comprises the following steps: and (3) taking deionized water with the mass 5 times of that of the dopamine, dissolving the dopamine, sodium silicate and a silane coupling agent in the deionized water, adjusting the pH to 8.0, uniformly mixing and stirring, and standing for 4 hours to prepare the waterproof agent.

And step two, mixing water, cement, heat-preservation light filler, cyclodextrin, hydrogenated castor oil and a waterproof agent according to the formula amount, adding a foaming agent under the constant temperature condition of 70 ℃, standing, foaming at constant temperature, and preserving heat for 4 hours to obtain the foamed concrete.

Performance test

The concrete samples obtained in examples 1 to 12 and comparative examples 1 to 4 were subjected to the compressive strength test, the thermal conductivity test and the water contact angle test, and the results of the tests are shown in Table 3.

The compression strength of the sample is tested according to JC/T1062-2007 foam concrete block and the thermal conductivity is tested according to GB/T10294-2008 testing thermal insulation material steady-state thermal resistance and related characteristic determination heat shield plate method, and the size of the sample is 300mm multiplied by 25 mm.

Testing the water contact angle according to the standard GB/T30447-2013, wherein the contact angle is as follows: dropping liquid on the solid surface, taking a tangent line of a gas-liquid interface at a solid-liquid-gas triple intersection, wherein an included angle between a secondary tangent line and a solid-liquid boundary line is a contact angle, the contact angle reflects the infiltration degree of the liquid on the solid, and if the contact angle is less than 90 degrees, the solid surface is hydrophilic, namely the liquid is easier to wet the solid, and the smaller the angle is, the better the wettability is; if the contact angle is greater than 90 deg., the surface of the solid is hydrophobic, i.e., the liquid does not readily wet the solid, the better the hydrophobicity.

TABLE 3 results of the experiment

	Compressive strength/MPa	Thermal conductivity W/(m.K)	Water contact angle/° c
				Example 1	10.11	0.057	108
Example 2	10.1	0.057	108
				Example 3	10.2	0.055	111
Example 4	10.32	0.052	114
				Example 5	10.3	0.051	114
Example 6	10.31	0.05	114
				Example 7	10.35	0.05	116
Example 8	10.4	0.041	116
				Example 9	10.5	0.041	115
Example 10	10.7	0.04	118
				Example 11	10.9	0.04	116
Example 12	11	0.04	118
				Comparative example 1	8	0.07	105
Comparative example 2	8.5	0.082	105
				Comparative example 3	8.9	0.067	98
Comparative example 4	8.1	0.075	101

As can be seen from examples 1 to 4 and Table 3, the compressive property of concrete can be improved to a certain extent by optimizing the components of the hydrogenated castor oil and the proportion of the waterproofing agent, and the waterproofing performance of concrete can be remarkably improved by optimizing the waterproofing agent. It can be seen from examples 5 to 7 that the components of the foaming agent are optimized, so that a large number of smile bubbles are generated in the concrete stirring process, the internal porosity of the concrete can be improved, and the heat insulation performance of the concrete can be improved. It can be seen from examples 7-10 and table 3 that the thermal conductivity of the concrete is decreased to a certain extent after the cyclodextrin is added, and the thermal insulation performance of the concrete is increased to a certain extent, and the cyclodextrin can cooperate with other raw material components in the application to improve the thermal stability of the concrete and improve the thermal insulation performance of the concrete. As can be seen from examples 10 to 12 and Table 3, the heat insulating property of the concrete can be further improved by optimizing the component ratios of the heat insulating lightweight filler.

It can be seen from the combination of example 1 and comparative example 1 and the combination of table 3 that the addition of hydrogenated castor oil has a certain influence on the strength of concrete, because the hydrogenated castor oil has thickening and slow-release effects, not only can change the fluidity of concrete, but also can reduce the hydration heat generated in the cement hydration process, so as to play a slow-release role, and simultaneously, the hydrogenated castor oil and the heat-insulating light filler cooperate to play a reinforcing role. Hydrogenated castor oil also has good lubricity, so that a concrete system is dispersed more uniformly, and a certain degree of hydrophobic effect is achieved.

As can be seen by combining example 1 and comparative example 2 and Table 3, the sodium dodecylbenzenesulfonate is a commonly used foaming agent, and the compressive strength and the thermal insulation performance of the concrete prepared by the sodium dodecylbenzenesulfonate are poor, while the compressive strength and the thermal insulation performance of the concrete prepared by the foaming agent of the present application are better when the alkyl glucoside and the tetrahydrofurfuryl alcohol are compounded, wherein the decyl glucoside and the tetrahydrofurfuryl alcohol have the best compounding effect.

Combining example 1 and comparative example 3 and table 3, it can be seen that the addition of dopamine has a significant effect on the water resistance of concrete and has a certain effect on the heat insulation performance of concrete, mainly because dopamine undergoes self-polymerization under alkaline conditions to form a binding liquid containing polydopamine, and after the silane coupling agent is added, the polydopamine and the silane coupling agent undergo a reaction to form a hydrophobic surface in cooperation with sodium silicate, and because the silane coupling agent and the polydopamine have a covalent interaction, the hydrophobic surface formed by the polydopamine has good hydrophobicity and stability, and the water resistance performance of concrete is significantly improved.

By combining example 1 and comparative example 4 and table 3, it can be seen that the waterproof agent prepared by the preparation method specified in the present application can significantly improve the waterproof performance of concrete, and the foamed concrete prepared by the preparation method specified in the present application has good heat insulation performance and high product quality.

As can be seen from examples 1 to 12 and comparative examples 1 to 4 in combination with Table 3, the foamed concrete prepared by using the raw material components and the specific preparation method of the present application has good thermal insulation performance and good waterproof performance.

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 (6)

1. The heat-preservation light foamed concrete is characterized by comprising the following components in parts by weight: 60-90 parts of water, 100-200 parts of cement, 3.6-6 parts of foaming agent, 2-4 parts of hydrogenated castor oil, 3-8 parts of waterproof agent and 20-45 parts of heat-insulating light filler, wherein the waterproof agent comprises the following components in parts by weight: 1.2-2.5 parts of sodium silicate, 0.8-2 parts of silane coupling agent and 1-3.5 parts of dopamine, wherein the foaming agent comprises alkyl glucoside and tetrahydrofurfuryl alcohol, and the mass ratio of the alkyl glucoside to the tetrahydrofurfuryl alcohol is 1 (0.8-2);

the preparation method of the waterproof agent comprises the following steps:

step 1, taking deionized water with the mass 5 times of that of dopamine, dissolving the dopamine in the deionized water, adjusting the pH value to 8.0-8.5, stirring for 2-3h, and standing for 2-5h to prepare a polydopamine solution;

and 2, equally dividing the polydopamine solution into 2 parts by mass, adding sodium silicate and a silane coupling agent into one part of the polydopamine solution, and uniformly mixing and stirring to obtain the waterproof agent.

2. The heat-insulating lightweight foamed concrete according to claim 1, wherein said alkyl glucoside is one selected from decyl glucoside, dodecyl glucoside and hexadecyl glucoside.

3. The heat-insulating light-weight foamed concrete according to claim 1, further comprising 1-3 parts by weight of cyclodextrin.

4. The heat-insulating light-weight foamed concrete according to claim 1, characterized in that the heat-insulating light-weight filler comprises the following components in parts by weight: 7-16 parts of perlite, 5-11 parts of wood fiber particles, 5-10 parts of glass bead particles and 3-8 parts of aerogel.

5. The heat-insulating lightweight foam concrete according to claim 4, wherein the wood fiber particles have a particle size of 40-100 meshes, and the glass bead particles have a particle size of 60-80 meshes.

6. The method for preparing the heat-insulating lightweight foamed concrete according to any one of claims 1 to 5, characterized by comprising the steps of:

step one, preparing a waterproof agent;

mixing the waterproof agent, cyclodextrin, hydrogenated castor oil and the residual 1/2 polydopamine solution according to the formula amount, adding a foaming agent for foaming under the constant temperature condition of 50-65 ℃, and preserving heat for 30-50min to prepare slurry;

and step three, uniformly stirring and mixing water, cement and the heat-preservation lightweight filler according to the formula amount, adding the slurry, mixing and homogenizing, heating to 70-85 ℃, preserving heat for 4-8 hours, and then demoulding to obtain the foamed concrete.