CN112142497B

CN112142497B - Durable foam concrete

Info

Publication number: CN112142497B
Application number: CN202010821592.9A
Authority: CN
Inventors: 请求不公布姓名
Original assignee: Guangzhou Tianyuan Concrete Co ltd
Current assignee: Guangzhou Tianyuan Concrete Co ltd
Priority date: 2019-10-22
Filing date: 2019-10-22
Publication date: 2023-05-16
Anticipated expiration: 2039-10-22
Also published as: CN112125701A; CN112142497A; CN110668841A; CN110668841B

Abstract

The invention discloses durable foam concrete, and belongs to the technical field of building materials. When the product is prepared, raw materials are weighed first, and water in the raw materials is equally divided into three parts; mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite and 2/3 of water, and then kneading for 45-60 min with high viscosity to obtain a kneaded material; heating the kneaded material to 55-75 ℃, adding a foaming agent, a foam stabilizer and the rest 1/3 of water, stirring and mixing, injection molding, standing for foaming, curing and demolding to obtain a blank; adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.3-0.5 MPa, heating to 85-95 ℃, performing heat preservation reaction, and discharging to obtain the durable foam concrete. The product obtained by the application has good mechanical properties, and the product foam strength also has good tolerance performance on the resistance capability of moisture and temperature.

Description

Durable foam concrete

Technical Field

The invention discloses durable foam concrete, and belongs to the technical field of building materials.

Background

The foam concrete is mainly made of calcareous materials (cement, lime) and siliceous materials (quartz sand, granulated blast furnace slag, fly ash, shale and the like), and is added with a proper amount of air entraining agent and the like, and is made into the porous ultra-light material through proportioning, stirring, pouring, gas generating and cutting.

Cement is the main cementing material in foam concrete and is also the main strength source of foam concrete, and plays a role in cementing in foam concrete. In general, the higher the strength grade of the cement used, the higher the compressive strength of the foam concrete produced. The cement for preparing the foam concrete has various types, and common silicate cement, slag silicate cement, fly ash silicate cement and the like can be used for preparing the foam concrete.

The foaming agent is an indispensable component for preparing foam concrete, and the quality of the foam concrete is largely determined by the performance of the foaming agent. The foaming agent is both a solid foaming agent and a liquid foaming agent. The types of blowing agents currently in common use are mainly: aluminum powder, surfactants, proteins.

At present, the manufacturing method of the foam concrete mainly comprises the following two steps: one method is to prepare a foam and mix the prepared foam with mortar, which is also called a pre-foam mixing method. The main process steps for manufacturing the foam concrete by the prefabricated foam mixing method comprise the following three steps: firstly, preparing cement mortar; then preparing foam; finally, the mortar and the foam are mixed and concrete is poured.

Another method is that mixing and foaming of concrete are performed simultaneously, which is called a mixing and stirring method. The main production process of the preparation method comprises three steps: firstly, preparing foaming agent cement mortar, then prefabricating and pouring the prepared mortar, and finally, standing and foaming the poured green body.

However, the product prepared by the raw materials and the preparation process has poor durability, and foam is easy to collapse in the long-term use process of the product, so that concrete gradually collapses and fails, and the service life of the product is influenced.

Disclosure of Invention

The invention mainly solves the technical problems that: aiming at the defects that the foam structure is unstable, collapse is easy to occur and the product performance is further deteriorated and the service life of the product is seriously influenced along with continuous invasion of moisture and carbon dioxide in the external environment in the preparation and use processes of the traditional foam concrete, the durable foam concrete and the preparation method thereof are provided.

In order to solve the technical problems, the invention adopts the following technical scheme:

the durable foam concrete comprises the following raw materials in parts by weight:

50 to 60 portions of cement

10 to 20 portions of carbonized rice hull fiber

3-5 parts of foaming agent

1 to 2 parts of foam stabilizer

4-6 parts of microcrystalline cellulose

5 to 10 portions of mirabilite

50 to 60 portions of water

10 to 15 parts of silicate

The preparation process of the durable foam concrete comprises the following steps:

(1) Weighing the components according to the composition of the raw materials; and equally dividing the water into three portions;

(2) Mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite and 2/3 of water, and then kneading for 45-60 min with high viscosity to obtain a kneaded material;

(3) Heating the kneaded material to 55-75 ℃, adding a foaming agent, a foam stabilizer and the rest 1/3 of water, stirring and mixing, injection molding, standing for foaming, curing and demolding to obtain a blank;

(4) Adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.3-0.5 MPa, heating to 85-95 ℃, performing heat preservation reaction, and discharging to obtain the durable foam concrete.

In the preparation process of the product, the technical scheme of the invention strictly limits the addition sequence of moisture, and aims to realize interaction among the components by utilizing mutual friction among the components in a high-viscosity state in the high-viscosity kneading process of the step 2, so that the surface structures of cement, rice hull fiber, microcrystalline cellulose and the like are changed, the increase of the specific surface area of the surfaces of the components is facilitated, the mutual adsorption effect is improved, the rapid formation of a gel body in the subsequent gelation process is facilitated, foam collapse in the preparation process of the product is avoided, and the internal porosity of the product is improved;

in addition, after the product is cured, silicate gradually permeates into the pores of the concrete under the action of certain pressure, and at the temperature, the mirabilite or the combined water in the concrete is gradually converted into free water, once the free water meets the silicate in the pores, the silicate is hydrolyzed to form silicon dioxide crystals, and the pores are blocked, so that the corrosion of the product to the concrete caused by factors such as moisture, carbon dioxide in the air and the like in the use process of the product is effectively avoided, and the service life of the product is prolonged; furthermore, after part of silicate is permeated into the foam concrete, the hydrolysate can reinforce the foam structure, so that collapse failure of the foam structure in the use process is effectively avoided, and the service life of the product is further prolonged.

The durable foam concrete comprises sepiolite with the mass of 5-10% of cement.

The sepiolite is acid-treated sepiolite; the treatment process of the acid-treated sepiolite comprises the following steps: sepiolite and hydrochloric acid with mass fraction of 1-10% are mixed according to mass ratio of 1: 20-1: 50, carrying out hydrothermal reaction, filtering, washing, drying and roasting to obtain the acid-treated sepiolite.

According to the technical scheme, the sepiolite is introduced, and can be quickly swelled and dispersed after meeting water to form an irregular sheet structure, so that the system is quickly foamed, and liquid with certain viscosity and stability is formed, and in the foaming process, the foaming effect is enhanced, and a good foam stabilizing effect can be achieved;

the sepiolite is further subjected to acidification treatment, magnesium ions in a sepiolite skeleton structure are replaced by hydrogen ions in hydrochloric acid after the acidification treatment, so that Si-OH is generated by an Si-O skeleton, crystal water is lost, pore channels in the sepiolite are communicated, micropores develop into mesopores, further foaming of the sepiolite is facilitated in the foaming process, the newly generated Si-OH and a cement gelation system can further react to form silicate gel, the sepiolite and a gelation system which are distributed on a foam wall and are in sheet dissociation form a complete whole, the reinforcement of the foam structure is realized, the newly generated Si-OH has higher activity, the rapid occurrence of gelation reaction is facilitated, and the reinforcement of foam can be realized in the foaming process.

The preparation process of the carbonized rice hull fiber comprises the following steps: soaking rice hulls in water, freezing and squeezing to obtain a squeezed material, heating the squeezed material to 600 ℃, preserving heat and carbonizing, continuously heating to 1500 ℃, reacting at high temperature, and discharging to obtain carbonized rice hull fibers.

The technical scheme of the invention is that firstly, rice hulls are soaked in water, so that the inside of rice hull cells fully absorbs water, then freezing and squeezing are utilized, in the freezing process, water is coagulated to form ice crystals, and under the action of squeezing pressure, the ice crystals are disintegrated, and at the same time, rice hull fibers are dissociated into micro rice hull fibers with the size reaching the nanometer level; and because the rice hull fiber contains a silicon dioxide component naturally, silicon dioxide and carbon can form silicon carbide whiskers at a high temperature of 1500 ℃, the silicon dioxide and carbon can be added into concrete, so that a good strengthening effect on foam concrete can be realized, and residual silicon dioxide can participate in a gelation reaction of cement, so that the concrete can be quickly cured.

The foaming agent is any one of emulsifier OP-10, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, tween-6 or span-80.

The foam stabilizer is any one of gelatin, bovine serum albumin, cyclodextrin, carboxymethyl cellulose, polyethylene glycol, chitosan and polyvinyl alcohol.

The silicate is any one of methyl silicate, ethyl silicate or propyl silicate.

The durable foam concrete comprises succinonitrile accounting for 1-3% of the mass of cement; the succinonitrile is added simultaneously with the foaming agent and the foam stabilizer.

According to the technical scheme, the succinonitrile is introduced, the adding time of the succinonitrile is limited, after the succinonitrile is added, the elasticity of a foam liquid film in the foaming process is improved, and the liquid film can be better subjected to external force without cracking; in addition, the air bubbles can be insoluble in water, the liquid discharge rate of the liquid film is prolonged, the liquid film has certain self-repairing capability, foam collapse in the preparation process is effectively avoided, the internal porosity is improved, and meanwhile, the mechanical property of the product is effectively improved.

Detailed Description

Acid-treated sepiolite:

sepiolite and hydrochloric acid with mass fraction of 1-10% are mixed according to mass ratio of 1: 20-1: 50 is added into a hydrothermal kettle, the temperature is 160-180 ℃, the pressure is 1.8-2.6 MPa, after the hydrothermal reaction is carried out for 3-5 hours, filtering is carried out, a filter cake is collected, deionized water is used for washing the filter cake until the washing liquid is neutral, the washed filter cake is transferred into an oven, the temperature is 105-110 ℃ and dried to constant weight, the dried filter cake is transferred into a muffle furnace, and the temperature is 180-200 ℃ and the heat preservation roasting is carried out for 1-2 hours, thus obtaining the acid-treated sepiolite;

charring rice hull fiber:

rice hulls and water are mixed according to the mass ratio of 1:10 to 1:20, mixing and soaking for 3-6 hours, taking out rice hulls, freezing for 1-2 hours at the temperature of minus 20-minus 50 ℃, squeezing under the pressure of 10-20 MPa to obtain a squeezed material, transferring the squeezed material into a tubular furnace, carbonizing for 3-5 hours at the temperature of 600 ℃ under the protection of argon, continuously heating to 1500 ℃, reacting for 3-5 hours at high temperature, cooling to room temperature along with the furnace, and discharging to obtain carbonized rice hull fibers;

the product is as follows:

according to the weight portion, sequentially taking 50 to 60 portions of 42.5# ordinary Portland cement, 10 to 20 portions of carbonized rice hull fiber, 3 to 5 portions of foaming agent, 1 to 2 portions of foam stabilizer, 4 to 6 portions of microcrystalline cellulose, 5 to 10 portions of mirabilite, 50 to 60 portions of water (and equally dividing the water into three portions), 10 to 15 portions of silicate, 5 to 10 percent of acid-treated sepiolite by the mass of cement and 1 to 3 percent of succinonitrile by the mass of cement; the foaming agent is any one of emulsifier OP-10, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, tween-60 or span-80; the foam stabilizer is any one of gelatin, bovine serum albumin, cyclodextrin, carboxymethyl cellulose, polyethylene glycol, chitosan and polyvinyl alcohol; the silicate is any one of methyl silicate, ethyl silicate or propyl silicate;

mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite, acid-treated sepiolite and 2/3 of water, and adding the mixture into a kneader, and kneading the mixture for 45 to 60 minutes to obtain a kneaded material; then the kneaded material is moved into a mixer, the kneaded material is heated to 55-75 ℃, then a foaming agent, a foam stabilizer, succinonitrile and the rest 1/3 of water are added, and the mixture is stirred and mixed for 45-60 min under the condition that the rotating speed is 800-1500 r/min, and then the injection molding, the static stop foaming, the maintenance and the demoulding are carried out, so as to obtain a blank body; adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.3-0.5 MPa, heating to 85-95 ℃, reacting for 3-5 h while maintaining the temperature, and discharging to obtain the durable foam concrete.

Example 1

Acid-treated sepiolite:

sepiolite and hydrochloric acid with the mass fraction of 1% are mixed according to the mass ratio of 1:20, adding the mixture into a hydrothermal kettle, carrying out hydrothermal reaction for 3 hours at 160 ℃ and under the pressure of 1.8MPa, filtering, collecting a filter cake, washing the filter cake with deionized water until washing liquid is neutral, transferring the washed filter cake into a baking oven, drying the filter cake to constant weight at 105 ℃, transferring the dried filter cake into a muffle furnace, and carrying out heat preservation and baking for 1 hour at 180 ℃ to obtain the acid-treated sepiolite;

charring rice hull fiber:

rice hulls and water are mixed according to the mass ratio of 1:10, mixing and soaking for 3 hours, taking out rice hulls, freezing for 1 hour at the temperature of minus 20 ℃, squeezing under the pressure of 10MPa to obtain a squeezed material, transferring the squeezed material into a tubular furnace, carbonizing for 3 hours at the temperature of 600 ℃ under the protection of argon, continuously heating to 1500 ℃, reacting for 3 hours at high temperature, cooling to room temperature along with the furnace, and discharging to obtain carbonized rice hull fibers;

the product is as follows:

according to the weight portion, sequentially taking 50 portions of 42.5# ordinary Portland cement, 10 portions of carbonized rice hull fiber, 3 portions of foaming agent, 1 portion of foam stabilizer, 4 portions of microcrystalline cellulose, 5 portions of mirabilite, 51 portions of water (and equally dividing the water into three portions), 10 portions of silicate, 5% of acid-treated sepiolite by mass of cement and 1% of succinonitrile by mass of cement; the foaming agent is an emulsifier OP-10; the foam stabilizer is gelatin; the silicate is methyl silicate;

mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite, acid-treated sepiolite and 2/3 of water, adding into a kneader, and kneading for 45min to obtain a kneaded material; then the kneaded material is moved into a mixer, the kneaded material is heated to 55 ℃, then a foaming agent, a foam stabilizer, succinonitrile and the rest 1/3 of water are added, and after stirring and mixing for 45 minutes under the condition that the rotating speed is 800r/min, the injection molding, the static stopping foaming, the maintenance and the demoulding are carried out, so as to obtain a blank body; adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.3MPa, heating to 85 ℃, preserving heat, reacting for 3 hours, and discharging to obtain the durable foam concrete.

Example 2

Acid-treated sepiolite:

sepiolite and hydrochloric acid with mass fraction of 5% are mixed according to mass ratio of 1:30, adding the mixture into a hydrothermal kettle, carrying out hydrothermal reaction for 4 hours at the temperature of 170 ℃ and the pressure of 2.2MPa, filtering, collecting a filter cake, washing the filter cake with deionized water until washing liquid is neutral, transferring the washed filter cake into a baking oven, drying the filter cake to constant weight at the temperature of 108 ℃, transferring the dried filter cake into a muffle furnace, and carrying out heat preservation roasting for 1.5 hours at the temperature of 190 ℃ to obtain acid-treated sepiolite;

charring rice hull fiber:

rice hulls and water are mixed according to the mass ratio of 1:15, mixing and soaking for 4 hours, taking out rice hulls, freezing for 1.5 hours at the temperature of minus 30 ℃, squeezing under the pressure of 15MPa to obtain a squeezed material, transferring the squeezed material into a tubular furnace, carbonizing for 4 hours under the condition of 600 ℃ under the protection of argon, continuously heating to 1500 ℃, reacting for 4 hours at high temperature, cooling to room temperature along with the furnace, and discharging to obtain carbonized rice hull fibers;

the product is as follows:

according to the weight portion, 55 portions of 42.5# ordinary Portland cement, 15 portions of carbonized rice hull fiber, 4 portions of foaming agent, 1.5 portions of foam stabilizer, 5 portions of microcrystalline cellulose, 8 portions of mirabilite, 57 portions of water (and equally dividing the water into three portions), 12 portions of silicate, 6 percent of acid-treated sepiolite by mass of cement and 2 percent of succinonitrile by mass of cement are sequentially taken; the foaming agent is sodium dodecyl benzene sulfonate; the foam stabilizer is cyclodextrin; the silicate is ethyl silicate;

mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite, acid-treated sepiolite and 2/3 of water, adding into a kneader, and kneading for 50min to obtain a kneaded material; then the kneaded material is moved into a mixer, the kneaded material is heated to 65 ℃, then a foaming agent, a foam stabilizer, succinonitrile and the rest 1/3 of water are added, and after stirring and mixing for 55 minutes under the condition that the rotating speed is 1200r/min, the injection molding, the static stopping foaming, the maintenance and the demoulding are carried out, thus obtaining a blank; adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.4MPa, heating to 90 ℃, preserving heat, reacting for 4 hours, and discharging to obtain the durable foam concrete.

Example 3

Acid-treated sepiolite:

sepiolite and hydrochloric acid with the mass fraction of 10% are mixed according to the mass ratio of 1:50, adding the mixture into a hydrothermal kettle, carrying out hydrothermal reaction for 5 hours at the temperature of 180 ℃ and the pressure of 2.6MPa, filtering, collecting a filter cake, washing the filter cake with deionized water until washing liquid is neutral, transferring the washed filter cake into a baking oven, drying the filter cake to constant weight at the temperature of 110 ℃, transferring the dried filter cake into a muffle furnace, and carrying out heat preservation and baking for 2 hours at the temperature of 200 ℃ to obtain acid-treated sepiolite;

charring rice hull fiber:

rice hulls and water are mixed according to the mass ratio of 1:20, mixing and soaking for 6 hours, taking out rice hulls, freezing for 2 hours at the temperature of minus 50 ℃, squeezing under the pressure of 20MPa to obtain a squeezed material, transferring the squeezed material into a tubular furnace, carbonizing for 5 hours at the temperature of 600 ℃ under the protection of argon, continuously heating to 1500 ℃, reacting for 5 hours at high temperature, cooling to room temperature along with the furnace, and discharging to obtain carbonized rice hull fibers;

the product is as follows:

according to the weight portion, 60 portions of 42.5# ordinary Portland cement, 20 portions of carbonized rice hull fiber, 5 portions of foaming agent, 2 portions of foam stabilizer, 6 portions of microcrystalline cellulose, 10 portions of mirabilite, 60 portions of water (and equally dividing the water into three portions), 15 portions of silicate, 10 percent of acid-treated sepiolite by mass of cement and 3 percent of succinonitrile by mass of cement are sequentially taken; the foaming agent is Tween-60; the foam stabilizer is carboxymethyl cellulose; the silicate is propyl silicate;

mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite, acid-treated sepiolite and 2/3 of water, adding into a kneader, and kneading for 60 minutes to obtain a kneaded material; then the kneaded material is moved into a mixer, the kneaded material is heated to 75 ℃, then a foaming agent, a foam stabilizer, succinonitrile and the rest 1/3 of water are added, and after stirring and mixing for 60 minutes under the condition that the rotating speed is 1500r/min, the injection molding, the static stopping foaming, the maintenance and the demoulding are carried out, so as to obtain a blank body; adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.5MPa, heating to 95 ℃, preserving heat, reacting for 5 hours, and discharging to obtain the durable foam concrete.

Comparative example 1

The difference between this comparative example and example 1 is that: sepiolite is not subjected to acid treatment, but adopts the following treatment modes:

sepiolite and water are mixed according to the mass ratio of 1:20 is added into a hydrothermal kettle, the temperature is 160 ℃, the pressure is 1.8MPa, the hydrothermal reaction is carried out for 3 hours, then the filtration is carried out, a filter cake is collected, deionized water is used for washing the filter cake until the washing liquid is neutral, the washed filter cake is transferred into a baking oven, the temperature is 105 ℃ and dried to constant weight, the dried filter cake is transferred into a muffle furnace, and the heat preservation and the baking are carried out for 1 hour at the temperature of 180 ℃ to obtain the pretreated sepiolite.

Comparative example 2

The difference between this comparative example and example 1 is that: the carbonization process of the carbonized rice hull fiber is different, and specifically comprises the following steps:

rice hulls and water are mixed according to the mass ratio of 1:10, mixing and soaking for 3 hours, taking out the rice hulls, freezing for 1 hour at the temperature of minus 20 ℃, squeezing under the pressure of 10MPa to obtain a squeezed material, transferring the squeezed material into a tubular furnace, carbonizing for 3 hours under the condition of 600 ℃ under the protection of argon, cooling to room temperature along with the furnace, and discharging to obtain the carbonized rice hull fiber.

Comparative example 3:

the difference between this comparative example and example 1 is that: the silicate was replaced with equal mass of absolute ethanol, the others remaining the same.

Comparative example 4:

the difference between this comparative example and example 1 is that: succinonitrile was not added and others remained the same.

The products obtained in examples 1-3 and comparative examples 1-4 were subjected to performance tests, and the specific test modes and test results are shown below:

the product was cut into a rectangular parallelepiped with dimensions of 100mm x 25mm and loaded at a loading rate of 0.3MPa/s until failure, and the compressive strength of the product was measured as shown in table 1:

	example 1	Example 2	Example 3	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4
								Compressive Strength/MPa	65.2	68.9	72.6	56.2	52.1	45.3	50.6

The product was subjected to a constant temperature and humidity standing for 3d at a relative humidity of 85% and a temperature of 45 ℃ and then to a constant temperature and humidity standing for 3d at room temperature, and after the above-mentioned cycle was repeated 50 times, the compressive strength of the product was again tested in the above-mentioned manner, and the test results are shown in table 2:

	example 1	Example 2	Example 3	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4
								Compressive Strength/MPa	62.1	67.6	71.3	50.1	42.2	41.2	36.5

As can be seen from the detection results in the table 1 and the table 2, the product obtained by the method has good mechanical properties, and after constant temperature and humidity treatment, the product can still maintain good mechanical properties, which indicates that the product has good resistance to moisture and temperature in foam strength;

compared with example 1, the sepiolite in comparative example 1 has no acidification treatment, so that the rate of the gelation reaction is influenced, the porosity in the sepiolite is also influenced, and the compressive strength of the finally obtained product is reduced until the product is eaten; comparative example 2 compared with example 1, since the rice hull fiber was not subjected to a high temperature reaction of 1500 ℃, no silicon carbide component was generated, thereby affecting the reinforcing effect; in the comparative example 3, silicate is not added, so that the foam structure cannot be effectively reinforced in the processing process of the product, and the mechanical property of the product is not obviously improved; in comparative example 4, the elasticity of the foam is reduced due to the lack of succinonitrile, and the foam is easy to collapse in the preparation process, so that the performance of the product is obviously reduced after constant temperature and humidity treatment.

Claims

1. The durable foam concrete is characterized by comprising the following raw materials in parts by weight:

60 parts of 42.5# ordinary Portland cement, 20 parts of carbonized rice hull fiber, 5 parts of foaming agent, 2 parts of foam stabilizer, 6 parts of microcrystalline cellulose, 10 parts of mirabilite and 60 parts of water, and equally dividing the water into three parts of 15 parts of silicate, wherein the durable foam concrete further comprises 10% of acid-treated sepiolite by mass of cement and 3% of succinonitrile by mass of cement; the foaming agent is Tween-60; the foam stabilizer is carboxymethyl cellulose; the silicate is propyl silicate;

the preparation method comprises the following steps:

(1) Weighing the components: weighing the components according to the raw material composition, and uniformly dividing water into three parts;

(2) High viscosity kneading:

A. acid treatment of sepiolite: sepiolite and hydrochloric acid with the mass fraction of 10% are mixed according to the mass ratio of 1:50, adding the mixture into a hydrothermal kettle, carrying out hydrothermal reaction for 5 hours at the temperature of 180 ℃ and the pressure of 2.6MPa, filtering, collecting a filter cake, washing the filter cake with deionized water until washing liquid is neutral, transferring the washed filter cake into a baking oven, drying the filter cake to constant weight at the temperature of 110 ℃, transferring the dried filter cake into a muffle furnace, and carrying out heat preservation and baking for 2 hours at the temperature of 200 ℃ to obtain acid-treated sepiolite;

B. preparing carbonized rice hull fibers: rice hulls and water are mixed according to the mass ratio of 1:20, mixing and soaking for 6 hours, taking out rice hulls, freezing for 2 hours at the temperature of minus 50 ℃, squeezing under the pressure of 20MPa to obtain a squeezed material, transferring the squeezed material into a tubular furnace, carbonizing for 5 hours at the temperature of 600 ℃ under the protection of argon, continuously heating to 1500 ℃, reacting for 5 hours at high temperature, cooling to room temperature along with the furnace, and discharging to obtain carbonized rice hull fibers;

C. preparation of the kneaded material: mixing cement, carbonized rice hull fibers, microcrystalline cellulose, mirabilite, acid-treated sepiolite and 2/3 of water, adding into a kneader, and kneading for 60 minutes to obtain a kneaded material;

(3) Heating and foaming: transferring the kneaded material into a mixer, heating the kneaded material to 75 ℃, adding a foaming agent, a foam stabilizer, succinonitrile and the rest 1/3 of water, stirring and mixing for 60min at the rotating speed of 1500r/min, and then carrying out injection molding, static stopping foaming, curing and demoulding to obtain a blank;

(4) And (3) pressurizing reaction: adding the green body and silicate into a reaction kettle, sealing, pressurizing to 0.5MPa, heating to 95 ℃, preserving heat, reacting for 5 hours, and discharging to obtain the durable foam concrete.