CN117383884A - Anti-seismic anti-cracking aerated concrete block and preparation method thereof - Google Patents

Abstract

The invention discloses an anti-seismic and anti-cracking aerated concrete block and a preparation method thereof, belonging to the technical field of building materials, and comprising the following raw materials in parts by weight: 65-80 parts of cement; 310-330 parts of sand; 65-80 parts of quicklime; 12-16 parts of gypsum; 0.6-0.7 part of aluminum powder; 0.5-0.7 part of water reducer; 3.5-5.0 parts of organic additive; 0.01-0.05 part of auxiliary foaming agent; 200-230 parts of water, and the aerated concrete has the advantages of small dry density, high compressive strength, strong mechanical property and low expansion rate, can completely utilize the existing equipment to perform experiments, and is economical and environment-friendly.

Description

Anti-seismic anti-cracking aerated concrete block and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to an anti-seismic and anti-cracking aerated concrete block and a preparation method thereof.

Background

The aerated concrete is a novel building material with light weight, multiple holes, heat preservation, heat insulation and good fireproof performance, the general weight is 500-700 kg/cubic meter, which is only equivalent to 1/4-1/3 of clay bricks and lime sand bricks, and 1/5 of common concrete, and the aerated concrete can be used as a bearing wall of a bottom layer building and a filling wall of a high-rise building.

However, the existing aerated concrete block has low compressive strength, shrinkage of about 0.4-0.7mm/m, large shrinkage and easy cracking, and no effective method exists at present.

The application number is 202011074860.1, the invention relates to a method for preparing aerated concrete by using recycled concrete aggregate and the aerated concrete, and discloses a method for preparing the aerated concrete by using the recycled concrete aggregate, which comprises the following steps: s1, pretreatment of recycled aggregate: weighing the recycled raw materials, and drying to obtain recycled aggregate; the regeneration raw materials are as follows: regenerating concrete powder, nano silica sol aqueous solution, hydroxypropyl distarch phosphate; s2, preparing slurry: taking water, adding slurry raw materials, ball milling to obtain fine slurry, adding recycled aggregate, quicklime powder and cement, and adding aluminum powder to obtain slurry; by the aid of the nano silica sol nano particles, although concrete pressure is increased, the reactivity is increased due to the large specific surface area of the nano particles, the reaction speed is increased, slurry thickening is fast, pouring stability is poor, and the porosity of the building block is reduced due to the filling effect of the nano particles, so that the aerated concrete building block with good performance is comprehensively judged.

The application number is 202211499704.9, the invention name is an environment-friendly crack-resistant aerated concrete block and a preparation method thereof, and 4-6 parts of expansion fiber are disclosed; 5.5-7.5 parts of anti-cracking fiber; 3-5 parts of mixed glue solution B; 65-85 parts of fly ash; 15-25 parts of lime; 8-15 parts of cement; 0.4-1 part of aluminum powder; 1-2 parts of water reducer; 28-34 parts of water; wherein the anti-cracking fiber is a mixed glue solution A modified fiber; the mixed glue solution A is composed of PAE, polyethylene glycol acrylate, MUF and protein powder, but in the preparation method, the technical scheme of stirring and mixing the swelling fiber, the fly ash, lime, cement, aluminum powder, a water reducing agent and water, adding the mixed solution, stirring and mixing to obtain slurry, pouring the slurry into a mould, standing for hardening, demoulding and cutting to obtain a blank is disclosed, but in general, aluminum powder is added at last after all materials are uniformly stirred, because the aluminum powder reacts with quicklime to generate hydrogen, and the speed is high, if the aluminum powder is stirred together with other materials, the long stirring time can cause the hydrogen to overflow to influence the porosity and the dry density.

Disclosure of Invention

In view of the above, the invention provides an anti-seismic and anti-cracking aerated concrete block and a preparation method thereof, and aims to prepare an aerated concrete block with small volume weight and high strength, namely, the aerated concrete block is mainly improved in cracking performance through three aspects on the basis of considering light dead weight and other original performances, on one hand, the shrinkage rate of the block is reduced, on the other hand, the mechanical strength of the block is increased, and on the other hand, the expansion and contraction effect generated by temperature difference is reduced, so that the anti-seismic and anti-cracking performance of the block is increased.

In order to achieve the above object, the present invention provides the following technical solutions:

an anti-seismic anti-cracking aerated concrete block comprises the following raw materials in parts by weight: 65-80 parts of cement; 310-330 parts of sand; 65-80 parts of quicklime; 12-16 parts of gypsum; 0.6-0.7 part of aluminum powder; 0.5-0.7 part of water reducer; 3.5-5.0 parts of organic additive; 0.01-0.05 part of auxiliary foaming agent; 200-230 parts of water.

The invention also has the following additional technical characteristics:

preferably, the organic additive is bisphenol A epoxy resin E44, a resin toughening agent and styrene-butadiene emulsion, and the mass ratio is 25:1:10.

Preferably, the auxiliary foaming agent is sodium bicarbonate.

Preferably, the feed comprises the following raw materials in parts by weight: 70 parts of cement; 320 parts of sand; 70 parts of quicklime; 14 parts of gypsum; 0.6 parts of aluminum powder; 4.2 parts of organic additive; 0.02 parts of auxiliary foaming agent; 0.6 parts of water reducer; 220 parts of water.

Preferably, the grain size of the sand is 50-150 meshes, the sand is quartz sand, and the sand contains 40-70 meshes with the mass fraction of 30% and 50-100 meshes with the mass fraction of 70%, so that the fluidity and the reactivity of fine sand are both considered, but if the fine sand is too much, the fine sand can react too quickly to cause suffocation, and therefore coarse sand is used for regulating the gas generation.

Preferably, the water reducer is an sulfamic acid high-efficiency water reducer.

The invention also provides a preparation method of the anti-seismic anti-cracking aerated concrete block, which comprises the following steps:

firstly, weighing each component, putting sand, gypsum and part of water into a stirrer to be uniformly mixed, adding cement and the rest of water to be uniformly mixed, adding quicklime to be uniformly mixed again, adding an organic additive to be uniformly mixed, finally adding aluminum powder and an auxiliary foaming agent to be uniformly stirred within one minute to obtain a mixture, and operating at room temperature;

secondly, pouring the mixture into a mould, and standing for 2-4 hours at 40-60 ℃ to obtain a primary concrete block; in this step

And thirdly, transferring the primary concrete block into an autoclave, curing for 2-4 hours under the conditions of the temperature of 60-80 ℃ and the pressure of 1.2-1.8MPa, cutting the block, heating to the temperature of 90-150 ℃ at 5 ℃/min, and curing for 6-8 hours under the conditions of the pressure of 1.2-3MPa, thus obtaining the aerated concrete block.

The reaction principle of the invention is as follows: the quick lime and the cement are stirred and then hydrated to generate hydroxide, after aluminum powder is added, the aluminum powder reacts with the hydroxide to generate hydrogen in stirring and form a pore structure in the slurry thickening process, and in the curing and heating process, the volume of gas is increased along with the temperature rise to form pores. The resin and the styrene-butadiene emulsion are added to enable the aluminum powder to emit gas and receive resistance, the porosity is reduced, the dry density is increased, so that the sodium bicarbonate is added to carry out auxiliary gas emission, the sodium bicarbonate reacts with cement to generate carbon dioxide, the carbon dioxide is subjected to reversible reaction, in the steam curing process, the carbon dioxide expands and overflows along with the temperature rise, the reaction balance is broken, and meanwhile, the aluminum powder and alkali are more conducive to generating hydrogen through the reaction due to the alkaline rise of concrete, the porosity is improved, and the volume weight is reduced. Thus, sodium bicarbonate has a dual role as an auxiliary gas generator.

In addition, the porosity of the aerated concrete is more than 50%, the mechanical property of the building block can be obviously improved by improving the strength of the pore partition wall, and as the bisphenol A type epoxy resin E44 is a thermosetting resin, the bisphenol A type epoxy resin E44 can be cured into a cross-linked network structure in the pore partition wall under the action of a resin toughening agent in the steam curing process, and the styrene-butadiene emulsion can play roles in bonding and filling cracks and reducing the shrinkage rate of the concrete.

Compared with the prior art, the invention has the advantages that:

the invention can fully utilize the existing equipment to carry out experiments, and is economical and environment-friendly; the aerated concrete has the advantages of small dry density, high compressive strength, strong mechanical property and low expansion rate.

Detailed Description

Some embodiments of the invention are disclosed below and one skilled in the art can, based on the disclosure herein, suitably modify the process parameters to achieve this. It is expressly noted that all such similar substitutions and modifications will be apparent to those skilled in the art, and are deemed to be included in the present invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those skilled in the relevant art that variations and modifications can be made in the methods and applications described herein, and in the practice and application of the techniques of this invention, without departing from the spirit or scope of the invention.

The materials in the following examples are described as follows:

the cement is P.O42.5R ordinary Portland cement, which is purchased from Jianghuai building materials science and technology Co., ltd;

sand: is quartz sand, which contains 30% of 40-70 mesh by mass and 70% of 50-100 mesh by mass, and is fed into mineral product processing factories in the Ministry of life;

quicklime: 200 mesh, purchased from Hebei Hui environmental protection technology Co., ltd;

gypsum: model P130, available from Lianyong City Pengwei thermal insulation building materials Co., ltd;

aluminum powder: model GLS-65, purchased from Shandong Sanpin aluminum technologies Co., ltd;

resin toughening agent: model SH-200-201, purchased from Guangzhou New rare metallurgical chemical Co., ltd;

water reducing agent: sulfamate high-efficiency water reducer is purchased from Fenyang hall (Shanghai) real company;

example blocks cube test blocks were prepared according to 100mm x 100mm specifications, three blocks per set.

Example 1

Preparation of aerated concrete Block 1

The following raw materials in parts by weight are taken: 70 parts of cement; 360 parts of sand; 70 parts of quicklime; 14 parts of gypsum; 0.6 parts of aluminum powder; 4.2 parts of organic additive; sodium bicarbonate 0.02 parts; 0.6 parts of water reducer; 220 parts of water; wherein the organic additive is bisphenol A type epoxy resin E44, resin toughening agent and styrene-butadiene emulsion, and the mass ratio is 25:1:10.

The aerated concrete block 1 is prepared according to the following steps:

firstly, weighing each component, putting sand, gypsum and half of water into a stirrer, stirring for 2 minutes, adding cement and the rest of water, continuously and uniformly mixing, wherein the cement is added in two times, the water is also added in two times, quicklime is added, stirring again for 1 minute, uniformly mixing, adding an organic additive, uniformly mixing, finally adding aluminum powder and an auxiliary foaming agent, uniformly stirring within 30 seconds, and obtaining a mixture, and operating at room temperature; namely 20-25 ℃;

secondly, pouring the mixture into a mould, and standing for 160min at 45 ℃ to obtain a primary concrete block;

and thirdly, transferring the primary concrete block into an autoclave, curing for 3 hours at the temperature of 65 ℃ and the pressure of 1.2MPa, cutting the primary concrete block into blocks, heating to the temperature of 110 ℃ at 5 ℃/min, and curing for 8 hours at the pressure of 1.4MPa to obtain the aerated concrete block 1.

Example 2

Preparation of aerated concrete Block 2

The following raw materials in parts by weight are taken: 75 parts of cement; 350 parts of sand; 70 parts of quicklime; 15 parts of gypsum; 0.6 parts of aluminum powder; 4.0 parts of organic additive; sodium bicarbonate 0.03 parts; 0.5 parts of water reducer; 230 parts of water; wherein the organic additive is bisphenol A type epoxy resin E44, resin toughening agent and styrene-butadiene emulsion, and the mass ratio is 25:1:10.

The aerated concrete block 2 is prepared according to the following steps:

firstly, weighing each component, putting sand, gypsum and half of water into a concrete mixer, stirring for 2 minutes, adding cement and the rest of water, stirring for 2 minutes, mixing, adding quicklime, stirring for 1 minute again, mixing, adding an organic additive, mixing, adding aluminum powder and an auxiliary foaming agent, stirring for 40 seconds, and obtaining a mixture, and operating at room temperature;

secondly, pouring the mixture into a mould, standing for 2 hours at 60 ℃, and carrying out foaming reaction of aluminum powder to obtain a primary concrete block;

and thirdly, transferring the primary concrete block into an autoclave, curing for 4 hours at the temperature of 70 ℃ and the pressure of 1.5MPa, cutting the primary concrete block into blocks, heating to the temperature of 100 ℃ at 5 ℃/min, and curing for 6 hours at the pressure of 2.0MPa to obtain the aerated concrete block 2.

Example 3

Preparation of aerated concrete Block 3

The following raw materials in parts by weight are taken: 65 parts of cement; 360 parts of sand; 66 parts of quicklime; 12 parts of gypsum; 0.7 parts of aluminum powder; 4.6 parts of organic additive; sodium bicarbonate 0.04 parts; 0.7 parts of water reducer; 210 parts of water; wherein the organic additive is bisphenol A type epoxy resin E44, resin toughening agent and styrene-butadiene emulsion, and the mass ratio is 25:1:10.

The aerated concrete block 3 is prepared according to the following steps:

firstly, weighing each component, putting sand, gypsum and half of water into a stirrer, stirring for 2 minutes, adding cement and the rest of water, continuously stirring for 2 minutes, uniformly mixing, adding quicklime, stirring for 1 minute again, uniformly mixing, adding an organic additive, uniformly mixing, finally adding aluminum powder and an auxiliary foaming agent, stirring uniformly within one minute, and obtaining a mixture, and operating at room temperature;

secondly, pouring the mixture into a mould, and standing for 4 hours at 40 ℃ to obtain a primary concrete block;

and thirdly, transferring the primary concrete block into an autoclave, curing for 3 hours at the temperature of 65 ℃ and the pressure of 1.3MPa, cutting the primary concrete block into blocks, heating to the temperature of 100 ℃ at 5 ℃/min, and curing for 8 hours at the pressure of 1.9MPa to obtain the aerated concrete block 3.

In order to clarify the advantages of the present experimental method,

comparative example 1 aerated concrete was prepared using conventional methods, i.e. without the addition of organic additives, sodium bicarbonate and water reducing agents, all other things being equal to example 1.

Comparative example 2: bisphenol a type epoxy resin E44 and a resin toughening agent were not added, and the other was the same as in example 1.

Comparative example 3: sodium bicarbonate was not added, and the other steps were the same as in example 1.

Comparative example 4: the styrene-butadiene emulsion was not added, and the other was the same as in example 1.

Example 4

Performance testing

The test was performed according to the following test method, and the test results are shown in table 1:

(1) Dry density: the test is carried out according to the method of the standard GB/T11969-2008 autoclaved aerated concrete performance test method, and the unit is kg/m3.

(2) Dry shrinkage value: the test was carried out according to the method of the standard GB/T11972-1997 method for aerated concrete drying shrinkage test, in mm/m.

(3) Split tensile strength: the split tensile strength of the block 28d in MPa was tested according to the method of the standard GB/T11971-1997 test method for mechanical Property of aerated concrete.

(4) Compressive strength: the compressive strength of the block 28d, in MPa, was tested according to the method of the standard GB/T11971-1997 test method for mechanical Properties of aerated concrete.

Table 1 results of the aerated concrete product performance test of each example

The comparative example 1 is a preparation method of the existing aerated concrete block, the comparative example 2 is not added with bisphenol A type epoxy resin E44 and resin toughening agent, the compressive strength is reduced compared with the examples 1 and 1, it is known that the epoxy resin E44 can greatly influence the mechanical properties of the block, because the bisphenol A type epoxy resin E44 and resin toughening agent are added into the concrete, the resin crosslinking solidification is carried out in the steam pressurizing stage, the mechanical strength of the wall of the block hole is enhanced, the compressive strength and splitting tensile strength of the block are increased, the compressive strength is reduced compared with the compressive strength of the comparative example 1, the dry density is reduced, the sodium bicarbonate can carry out auxiliary foaming action, and at the high temperature in the steam curing process, the carbon dioxide generated by sodium bicarbonate overflows the concrete to generate calcium carbonate so as to form bubbles, and the ammonium bicarbonate is selected as an auxiliary foaming agent, compared with other foaming agents such as a surface active foaming agent, the pore size is not formed, and the foaming process of aluminum powder is not hindered; the comparative example 3 is free of sodium bicarbonate, the dry density of the building block is obviously increased, the compressive strength is increased, the splitting tensile strength is increased, the sodium bicarbonate can play a role in assisting in foaming, and the relationship between the dry density and the mechanical property can be balanced and selected according to the requirement in specific use. Comparative example 4 was found to have a slightly reduced dry density and slightly reduced compressive strength without the addition of styrene-butadiene emulsion, but the dry expansion and contraction value was significantly increased, indicating that the styrene-butadiene emulsion can reduce the shrinkage of the block, making the block less prone to cracking, and also indicating that bisphenol a type epoxy resin E44 and the resin toughening agent also have the effect of reducing the shrinkage of the block. It is seen from the combination of examples 2 and 4 that the impact of the styrene-butadiene emulsion on the compressive properties of the block is almost unchanged, but the drying shrinkage performance and the splitting strength of the block can be obviously affected. The splitting tensile strength of the building block can be obviously improved under the combined action of the epoxy resin and the styrene-butadiene emulsion, because the epoxy resin is brittle, the styrene-butadiene emulsion can improve the impact-resistant tanning property, and the defect of the epoxy resin is overcome.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims (7)

1. The anti-seismic anti-cracking aerated concrete block is characterized by comprising the following raw materials in parts by weight: 65-80 parts of cement; 310-330 parts of sand; 65-80 parts of quicklime; 12-16 parts of gypsum; 0.6-0.7 part of aluminum powder; 0.5-0.7 part of water reducer; 3.5-5.0 parts of organic additive; 0.01-0.05 part of auxiliary foaming agent; 200-230 parts of water.

2. The anti-seismic and anti-cracking aerated concrete block according to claim 1, wherein the organic additive is bisphenol A type epoxy resin E44, a resin toughening agent and a styrene-butadiene emulsion according to a mass ratio of 25:1:10.

3. The earthquake-resistant and crack-resistant aerated concrete block of claim 1, wherein the auxiliary foaming agent is sodium bicarbonate.

4. The anti-seismic and anti-cracking aerated concrete block according to claim 1, which is characterized by comprising the following raw materials in parts by weight: 70 parts of cement; 320 parts of sand; 70 parts of quicklime; 14 parts of gypsum; 0.6 parts of aluminum powder; 4.2 parts of organic additive; 0.02 parts of auxiliary foaming agent; 0.6 parts of water reducer; 220 parts of water.

5. The earthquake-resistant and crack-resistant aerated concrete block of claim 1, wherein the sand has a particle size of 50-150 mesh.

6. The anti-seismic and anti-cracking aerated concrete block of claim 1, wherein the water reducer is a sulfamic acid high efficiency water reducer.

7. The method for preparing the anti-seismic and anti-cracking aerated concrete block according to any one of claims 1 to 6 is characterized by comprising the following steps:

firstly, weighing each component, putting sand, gypsum and part of water into a stirrer to be uniformly mixed, adding cement and the rest of water to be uniformly mixed, adding quicklime to be uniformly mixed again, adding an organic additive to be uniformly mixed, finally adding aluminum powder and an auxiliary foaming agent to be uniformly stirred within one minute to obtain a mixture, and operating at room temperature;

secondly, pouring the mixture into a mould, and standing for 2-4 hours at 40-60 ℃ to obtain a primary concrete block;

and thirdly, transferring the primary concrete block into an autoclave, curing for 2-4 hours under the conditions of the temperature of 60-80 ℃ and the pressure of 1.2-1.8MPa, cutting the block, heating to the temperature of 90-150 ℃ at 5 ℃/min, and curing for 6-8 hours under the conditions of the pressure of 1.2-3MPa, thus obtaining the aerated concrete block.