CN118271040A - A preparation process of high-strength foamed concrete - Google Patents

Abstract

The invention discloses a preparation process of high-strength foam concrete, which comprises the steps of adding water and sodium hydroxide into a stirrer, completely dissolving the sodium hydroxide, adding 0.03 to 0.1 part by mass of hydroxypropyl methyl cellulose, 0.05 to 0.2 part by mass of polyvinyl alcohol and 1 part by mass of palm fiber into a sodium hydroxide solution, adding cement and coal ash into the mixture, stirring, adding 180 to 594 parts by mass of the added cement and 120 to 600 parts by mass of the coal ash, adding 150 to 510 parts by mass of the added water, adding 0.5 part by mass of a high-efficiency water reducing agent into the mixture, stirring for ninety seconds, adding 0.4 to 0.7 part by mass of aluminum powder paste, obtaining foam concrete, naturally foaming the foam concrete in a mold frame, and demoulding after the strength of the foam concrete reaches the requirement, and cutting the foam concrete into blocks.

Description

A preparation process of high-strength foamed concrete

Technical Field

The present invention belongs to the technical field of concrete, and specifically relates to a preparation process of high-strength foamed concrete.

Background technique

During the construction process, foamed concrete has good pumpability, high compressive strength (0.5-22.2Mpa), good impact energy absorption performance, can make use of a large amount of industrial waste slag, and is inexpensive. Foamed concrete is a porous material, so it is also a good sound insulation and thermal insulation material. It can be used as a sound insulation layer in the floors of buildings, sound insulation boards on highways, and the top floors of underground buildings. It is widely used in floor and wall insulation. Foamed concrete is an inorganic material that does not burn, so it has good fire resistance. When used in buildings, it can improve the fire resistance of buildings.

However, the strength of common foam concrete is relatively low, and the concrete is prone to cracking after long-term use, thus affecting the durability of the entire building.

Summary of the invention

The purpose of the present invention is to provide a preparation process of high-strength foamed concrete, which is used for making high-strength foamed concrete.

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

A preparation process of high-strength foamed concrete, comprising the steps of:

Step 1, adding water and sodium hydroxide (NaOH) into a mixer, stirring to completely dissolve the sodium hydroxide, wherein the added sodium hydroxide is 1.6 to 2.8 parts by mass;

Step 2: Add 0.03 to 0.1 parts by mass of hydroxypropyl methylcellulose, 0.05 to 0.2 parts by mass of polyvinyl alcohol and 1 part by mass of brown fiber into the sodium hydroxide solution and stir evenly;

Step 3, adding cement and fly ash to the mixture prepared in step 2 and stirring at the same time until the cement and fly ash are uniformly mixed, wherein the weight of the added cement is 180 to 594 parts by mass, the weight of the fly ash is 120 to 600 parts by mass, and the weight of the added water is 150 to 510 parts by mass;

Step 4: add 0.5 parts by mass of a high-efficiency water reducer to the mixture prepared in step 3 and stir evenly, then add 0.4 to 0.7 parts by mass of aluminum powder paste and stir for 90 seconds to obtain foamed concrete;

Step 5: Place the foam concrete in the mold frame and allow it to foam naturally for 30 minutes;

Step 6: After the strength of the foam concrete reaches the required strength, demoulding is carried out, and then the foam concrete is cut into blocks.

Furthermore, high-efficiency water reducers reduce the amount of water used in making concrete by 15% and increase its strength by 30%.

Furthermore, a high-efficiency water reducing agent is added to the mixture prepared in step three and stirred evenly. The stirring speed of the mixer is 500 r/min, and the temperature inside the mixer is 35° C. to 45° C. during stirring.

Furthermore, hydroxypropyl methylcellulose is used to prevent the bubbles generated inside the foamed concrete from escaping, thereby reducing the possibility of stratification and segregation of the foamed concrete.

Furthermore, the palm fibers are used to increase the strength of the foamed concrete and prevent the foamed concrete from cracking.

Furthermore, polyvinyl alcohol is used to enhance the bonding strength between various materials inside the foam concrete.

Furthermore, in step three, cement and pulverized coal are added to the mixture prepared in step two and stirred simultaneously. The rotation speed of the mixer is 300 r/min. During the stirring process, the internal temperature of the mixer is 30° C. to 40° C.

Further, in step 1, the weight of sodium hydroxide selected is 2.6 parts by mass;

In step 2, 0.03 parts by weight of hydroxypropyl methylcellulose and 0.05 parts by weight of polyvinyl alcohol are selected;

In step 3, 180 parts by mass of cement, 120 parts by mass of fly ash, and 150 parts by mass of water are selected;

In step 4, 0.7 parts by weight of aluminum paste is used to prepare high-strength foam concrete for roof insulation.

Further, in step 1, the weight of the sodium hydroxide selected is 2.2 parts by mass;

In step 2, 0.07 parts by weight of hydroxypropyl methylcellulose and 0.140 parts by weight of polyvinyl alcohol are selected;

In step 3, 300 parts by mass of cement, 400 parts by mass of fly ash, and 322 parts by mass of water are selected.

In step 4, 0.55 parts by weight of aluminum paste is used to prepare high-strength foamed concrete for wall construction.

Further, in step 1, the weight of sodium hydroxide selected is 1.6 parts by mass;

In step 2, 0.1 parts by weight of hydroxypropyl methylcellulose and 0.2 parts by weight of polyvinyl alcohol are selected;

In step three, 400 parts by mass of cement, 500 parts by mass of fly ash, and 405 parts by mass of water are selected. In step four, 0.4 parts by mass of aluminum paste are selected to prepare high-strength foamed concrete for use in situations where higher strength requirements are required.

The beneficial effects of the present invention are as follows:

In the process of making foam concrete, high-efficiency water reducing agent is added to reduce water consumption and improve the strength of foam concrete.

By adding hydroxypropyl methylcellulose, the bubbles generated inside the foamed concrete can be prevented from escaping and the possibility of stratification and segregation of the foamed concrete can be reduced.

Polyvinyl alcohol is added to enhance the bonding strength between various materials inside the foam concrete.

By adding brown fibers to prevent the foam concrete from cracking, the strength of the foam concrete is increased, and the corrosion resistance and impact resistance of the foam concrete are improved.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

The present application provides a process for preparing high-strength foamed concrete, comprising the steps of:

Step 1, adding water and sodium hydroxide (NaOH) into a mixer, stirring to completely dissolve the sodium hydroxide, wherein the added sodium hydroxide is 1.6 to 2.8 parts by mass;

Step 2: Add 0.03 to 0.1 parts by mass of hydroxypropyl methylcellulose, 0.05 to 0.2 parts by mass of polyvinyl alcohol and 1 part by mass of brown fiber into the sodium hydroxide solution and stir evenly;

Step 3, adding cement and fly ash to the mixture prepared in step 2, and stirring at the same time until the cement and fly ash are uniformly mixed, wherein the weight of the added cement is 180 to 594 parts by weight, the weight of the fly ash is 120 to 600 parts by weight, and the weight of the added water is 150 to 510 parts by weight;

Step 4: add 0.5 parts by mass of a high-efficiency water reducer to the mixture prepared in step 3 and stir evenly, then add 0.4 to 0.7 parts by mass of aluminum powder paste and stir for 90 seconds to obtain foamed concrete;

Step 5: Place the foam concrete in the mold frame and allow it to foam naturally for 30 minutes;

Step 6: After the strength of the foam concrete reaches the required strength, demoulding is carried out, and then the foam concrete is cut into blocks.

In the actual process of making concrete, the amount of various materials added is selected according to the performance requirements of the foamed concrete to be prepared.

For the strength fcu,0 of the high-strength foamed concrete prepared according to the preparation process of the high-strength foamed concrete, the strength is calculated according to the following method:

fcu,0=fcu,k+1.645σ; Formula (1)

Where: fcu,0——concrete mix strength, unit: MPa;

fcu,k——standard value of concrete cube compressive strength, i.e. concrete strength grade value, unit: MPa;

σ——standard deviation of concrete strength, unit: MPa.

Note: The number of strength test specimens during calculation should not be less than 25.

When the concrete strength grade is C20 and C25, and the calculated value of the strength standard deviation σ is less than 2.5MPa, take σ=2.5MPa; when the concrete strength grade is equal to or greater than C30, and the calculated value of the strength standard deviation σ is less than 3.0MPa, take σ=3.0MPa.

When there is no statistical data to calculate the standard deviation of concrete strength, its value shall be taken in accordance with the provisions of the current national standard "Code for Construction and Acceptance of Concrete Structure Engineering" (GB50204).

Among them, high-efficiency water reducer reduces the water consumption in making concrete by 15% and increases the strength by 30%.

Wherein, a high-efficiency water reducing agent is added to the mixture prepared in step 3 and stirred evenly. The stirring speed of the mixer is 500 r/min, and the temperature inside the mixer is 35° C. to 45° C. during stirring.

Under certain materials and test conditions, as long as the concrete mixture is plastic, the strength of concrete depends on the amount of mixing water. Ordinary concrete is composed of water, cement, sand, stone and admixtures. There are three main technical parameters between the amounts of various materials, namely water-cement ratio (W/C), sand ratio and unit water consumption.

The water-cement ratio (W/C) refers to the weight ratio of water to cement in a unit concrete mixture. The water-cement ratio (W/C) plays a decisive role in the strength of plastic concrete.

When the amount of other materials is determined, the strength of plastic concrete depends on the amount of mixing water. The greater the amount of water, the greater the water-cement ratio and the lower the concrete strength.

When the amount of other materials is determined, adding high-efficiency water reducer can reduce the amount of water, reduce the water-cement ratio, and improve the strength of concrete. Specifically, when the amount of other materials is determined, adding high-efficiency water reducer can reduce the water consumption by 15% and improve the strength of foam concrete by 30%.

Among them, hydroxypropyl methylcellulose is used to prevent the escape of bubbles generated inside the foam concrete and reduce the possibility of stratification and segregation of the foam concrete.

Hydroxypropyl methylcellulose can keep the cement and fly ash in the foam concrete in a suspended state. The cement and fly ash will not sink completely to the bottom. The cement and fly ash in the foam concrete are evenly distributed inside the concrete. The bubbles between the various material particles in the foam concrete are evenly distributed along with the particle materials, which prevents the bubbles generated inside the foam concrete from escaping. By promoting the uniform distribution of cement, fly ash and bubbles inside the foam concrete, the possibility of stratification and segregation of the foam concrete is reduced.

Among them, brown fiber is used to prevent foam concrete from cracking and increase the strength of foam concrete.

Among them, polyvinyl alcohol is used to enhance the adhesion between various materials inside the foam concrete.

Wherein, in step three, cement and pulverized coal are added to the mixture prepared in step two and stirred simultaneously, the rotation speed of the mixer is 300r/min, and during the stirring process, the internal temperature of the mixer is 30°C to 40°C.

In one embodiment, a preparation process for high-strength foamed concrete is provided, and the high-strength foamed concrete produced is used for roof insulation. The specific steps are as follows: In this embodiment, 1 mass part is 1 kilogram.

In step 1, water and sodium hydroxide (NaOH) are added into a mixer and stirred to completely dissolve the sodium hydroxide, wherein the weight of the added sodium hydroxide is 2.6 kg.

In step 2, add 30 grams of hydroxypropyl methylcellulose, 50 grams of polyvinyl alcohol and 1 kilogram of palm fiber into the sodium hydroxide solution and stir evenly.

In step three, cement and fly ash are added to the mixture prepared in step two and stirred simultaneously until the cement and fly ash are evenly mixed, wherein 180 kg of cement, 120 kg of fly ash and 150 kg of water are added.

In step 4, 500 grams of high-efficiency water reducing agent is added to the mixture prepared in step 3 and stirred evenly, and then 700 grams of aluminum powder paste is added and stirred for 90 seconds to obtain foamed concrete, thereby preparing high-strength foamed concrete for roof insulation.

Based on the above method and the selected material ratio, the strength of the prepared high-strength foamed concrete is: 1.0 MPa.

The high-strength foamed concrete produced according to the above preparation process saves a total of 50 kg of cement and fly ash materials compared to the traditional production method, including 20 kg of cement and 30 kg of fly ash.

In another embodiment, a preparation process for high-strength foamed concrete is provided, and the high-strength foamed concrete produced is used for roof insulation. The specific steps are as follows: 1 mass part is 1 kilogram.

In step 1, water and sodium hydroxide (NaOH) are added into a mixer and stirred to completely dissolve the sodium hydroxide, wherein the weight of the added sodium hydroxide is 2.2 kg.

In step 2, add 70 grams of hydroxypropyl methylcellulose, 140 grams of polyvinyl alcohol and 1 kilogram of palm fiber into the sodium hydroxide solution and stir evenly.

In step three, cement and fly ash are added to the mixture prepared in step two and stirred simultaneously until the cement and fly ash are evenly mixed, wherein 300 kg of cement, 400 kg of fly ash and 322 kg of water are added.

In step 4, 500 grams of high-efficiency water reducing agent is added to the mixture prepared in step 3 and stirred evenly, and then 550 grams of aluminum powder paste is added and stirred for 90 seconds to obtain foamed concrete, and high-strength foamed concrete is prepared for wall construction.

Based on the above method and the selected material ratio, the strength of the prepared high-strength foamed concrete is: 5.0 MPa.

The high-strength foamed concrete produced according to the above preparation process can save a total of 100 kg of cement and fly ash materials compared to the traditional production method, including 40 kg of cement and 60 kg of fly ash.

In another embodiment, a preparation process for high-strength foamed concrete is provided, and the high-strength foamed concrete produced is used for roof insulation. The specific steps are as follows: 1 mass part is 1 kilogram.

In step 1, water and sodium hydroxide (NaOH) are added into a mixer and stirred to completely dissolve the sodium hydroxide, wherein the weight of the added sodium hydroxide is 1.6 kg.

In step 2, add 100 g of hydroxypropyl methylcellulose, 200 g of polyvinyl alcohol and 1 kg of palm fiber into the sodium hydroxide solution and stir evenly.

In step three, cement and fly ash are added to the mixture prepared in step two and stirred simultaneously until the cement and fly ash are evenly mixed, wherein the weight of the added cement is 400 kg, the weight of the fly ash is 500 kg, and the weight of the added water is 405 kg.

In step 4, 500 grams of high-efficiency water reducing agent is added to the mixture prepared in step 3 and stirred evenly, and then 400 grams of aluminum powder paste is added and stirred for 90 seconds to obtain foamed concrete. The prepared high-strength foamed concrete is used in occasions with higher strength requirements, for example, it can be used as a support column.

Based on the above method and the selected materials, the strength of the prepared high-strength foamed concrete is: 7.5MP.

The high-strength foamed concrete produced according to the above preparation process can save a total of 200 kg of cement and fly ash materials compared to the traditional production method, including 80 kg of cement and 120 kg of fly ash.

In the process of making foamed concrete, high-efficiency water reducer is added to reduce water consumption and improve the strength of foamed concrete. Hydroxypropyl methylcellulose is added to prevent the escape of bubbles generated inside the foamed concrete and reduce the possibility of stratification and segregation of the foamed concrete. Polyvinyl alcohol is added to enhance the bonding force between various materials inside the foamed concrete. Brown fiber is added to prevent cracking of foamed concrete, increase the strength of foamed concrete, and improve the corrosion resistance and impact resistance of foamed concrete.

By adding high-efficiency water reducing agent, hydroxypropyl methylcellulose, polyvinyl alcohol and palm fiber, the possibility of mold collapse during the production process can be reduced and the yield of finished products can be improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. A process for preparing high-strength foamed concrete, characterized in that it comprises the following steps: Step 1, adding water and sodium hydroxide (NaOH) into a mixer, stirring to completely dissolve the sodium hydroxide, wherein the added sodium hydroxide is 1.6 to 2.8 parts by mass; Step 2: Add 0.03 to 0.1 parts by mass of hydroxypropyl methylcellulose, 0.05 to 0.2 parts by mass of polyvinyl alcohol and 1 part by mass of brown fiber into the sodium hydroxide solution and stir evenly; Step 3, adding cement and fly ash to the mixture prepared in step 2 and stirring at the same time until the cement and fly ash are uniformly mixed, wherein the added cement is 180 to 594 parts by mass, the fly ash is 120 to 600 parts by mass, and the added water is 150 to 510 parts by mass; Step 4: add 0.5 parts by mass of a high-efficiency water reducer to the mixture prepared in step 3 and stir evenly, then add 0.4 to 0.7 parts by mass of aluminum powder paste and stir for 90 seconds to obtain foamed concrete; Step 5: Place the foam concrete in the mold frame and allow it to foam naturally for 30 minutes; Step 6: After the strength of the foam concrete reaches the required strength, demoulding is carried out, and then the foam concrete is cut into blocks. 2. The preparation process of high-strength foamed concrete according to claim 1 is characterized in that the high-efficiency water reducing agent reduces the water consumption in making concrete by 15% and increases the strength by 30%. 3. The process for preparing high-strength foamed concrete according to claim 1 is characterized in that a high-efficiency water reducing agent is added to the mixture prepared in step 3 and stirred evenly, the stirring speed of the mixer is 500 r/min, and the temperature inside the mixer is 35° C. to 45° C. during stirring. 4. The process for preparing high-strength foamed concrete according to claim 1, characterized in that hydroxypropyl methylcellulose is used to prevent the bubbles generated inside the foamed concrete from escaping, thereby reducing the possibility of stratification and segregation of the foamed concrete. 5. The process for preparing high-strength foamed concrete according to claim 1, characterized in that the palm fiber is used to prevent the foamed concrete from cracking and increase the strength of the foamed concrete. 6. The process for preparing high-strength foamed concrete according to claim 1, characterized in that polyvinyl alcohol is used to enhance the bonding strength between various materials inside the foamed concrete. 7. The process for preparing high-strength foamed concrete according to claim 1 is characterized in that, in step 3, cement and pulverized coal are added to the mixture prepared in step 2 and stirred simultaneously, the rotation speed of the mixer is 300 r/min, and during the stirring process, the internal temperature of the mixer is 30° C. to 40° C. 8. The process for preparing high-strength foamed concrete according to claim 1, characterized in that: In step 1, the weight of sodium hydroxide selected is 2.6 parts by mass; In step 2, 0.03 parts by weight of hydroxypropyl methylcellulose and 0.05 parts by weight of polyvinyl alcohol are selected; In step 3, 180 parts by mass of cement, 120 parts by mass of fly ash, and 150 parts by mass of water are selected; In step 4, 0.7 parts by weight of aluminum paste is used to prepare high-strength foam concrete for roof insulation. 9. The process for preparing high-strength foamed concrete according to claim 1, characterized in that: In step 1, the weight of sodium hydroxide selected is 2.2 parts by mass; In step 2, 0.07 parts by weight of hydroxypropyl methylcellulose and 0.14 parts by weight of polyvinyl alcohol are selected; In step 3, 300 parts by mass of cement, 400 parts by mass of fly ash, and 322 parts by mass of water are selected; In step 4, 0.55 parts by weight of aluminum paste is used to prepare high-strength foamed concrete for wall construction. 10. The process for preparing high-strength foamed concrete according to claim 1, characterized in that: In step 1, the weight of sodium hydroxide selected is 1.6 parts by mass; In step 2, 0.1 parts by weight of hydroxypropyl methylcellulose and 0.2 parts by weight of polyvinyl alcohol are selected; In step three, 400 parts by mass of cement, 500 parts by mass of fly ash, and 405 parts by mass of water are selected. In step four, 0.4 parts by mass of aluminum paste are selected to prepare high-strength foamed concrete for use in situations where higher strength requirements are required.