Construction technology of foam concrete cushion

1. Grassroots cleanup

Use broom, shovel and other tools to clean the foam concrete base floor slab, so that there is no debris, hollowing, sanding, falling ash and other phenomena.

2. Elevation control and finished product protection

Before pouring the foam concrete cushion, a foam concrete block with the same proportion as the ground cushion concrete must be prefabricated in advance for ground reinforcement. The prefabricated height of the foam block is the design cushion height -5mm, so that cement mortar can be used on site. Fix the bottom and level it for use. Reinforce the ground according to the design requirements and the +50mm line in the building, and the setting principle is a plum-shaped layout. After the ground is reinforced, the finished products and semi-finished products of the previous process must be protected (such as the door, the lower sill of the fire door frame, the finished putty wall, etc.) and wrapped in advance to avoid pollution.

3. Formwork support and grassroots watering and moistening

According to the design requirements, the side formwork is supported according to the construction scope of the foam concrete cushion (such as: 300mm from the bathroom door, the kitchen door, the root of the radiator, etc.). The formwork is supported by square wood and bamboo plywood. It is necessary to ensure the verticality and flatness of the panel. After the formwork support is completed, water the ground base to moisten. Because the foam concrete has a low water absorption rate, it is not advisable to water too much to ensure that the ground is wet.

4. Production of foam concrete

(1) Production of foam

The foam preparation adopts a special preparation machine (foam generator). The preparation principle is a physical method, and the foaming agent is input into the automatic foaming system through an air compressor to prepare foam.

(2) Production mixture

The foam concrete mixture preparation machinery is selected according to the needs of the project. First, add a certain amount of water into the mixer, and then put the weighed cement and admixtures into the mixer for mixing, and the time is not less than 2 minutes.

(3) Form foam concrete

After mixing the mixed material evenly, it is mixed with the foaming agent in the pipeline and transported by the high-pressure pump to the construction site for pouring and molding.

5. Pouring molding

The cleaned ground is first watered and moistened, and then the configured foamed concrete is pumped on site to the corresponding construction floor to pour the ground cushion. During the pouring, two people work at the same time, and one person holds the pouring pipe for pouring. The ground cushion and the pouring surface should be leveled and formed at one time. Another person will hold a 2m scraper until the pouring reaches the calibrated height, and then smooth the newly poured concrete from the inside to the outside. After survival, the finished product must be protected and the passage must be temporarily closed. In order to avoid cross-working damage. Foamed concrete is a viscous fluid, which contains a lot of air and adsorbed water. The discharge pipe shall not come and go in the foam concrete to avoid destroying the air bubbles. The formwork can be removed only after the foam concrete has solidified. The foamed concrete must be used up within 1 hour after it is mixed, otherwise it cannot be used continuously.

6. Finished product protection and maintenance

After the foam concrete cushion is poured, the passages, entrances and other parts must be sealed, and designated for 24-hour care, and only professional maintenance personnel are allowed to enter and exit during the care. After the foamed concrete cushion is poured and formed for 12 to 14 hours, it shall be maintained by moisturizing and watering, and the curing time shall not be less than 72 hours.

Quality Assurance Measures

1. The types and specifications of foamed concrete should comply with the design and relevant standards. For the foamed concrete foamed on site, the mixing ratio should be accurately measured and evenly mixed, and its thermal conductivity, density, and compressive strength should be randomly witnessed and sent for inspection.

2. Before the large-scale construction of the project, a model guide system must be adopted. The model can only be promoted in a large area after the model technology is qualified, and the test block must be kept for compressive strength test when the model is made, and it can be used only after it is qualified.

3. The "three inspection system" must be strictly implemented during the construction process, that is, self-inspection, mutual inspection, and hand-over inspection. The next process can only be carried out after passing the inspection.

4. Tap water or purified water must be used for construction water. It is strictly forbidden to mix acidic water into the foaming agent to avoid chemical reactions and affect the foaming effect of the foaming agent.

5. After the foam concrete is poured, the entrance must be closed and a special person must be assigned to take care of it for 24 hours. It is forbidden to go up before the final setting. After reaching the strength, a special person must be dispatched for maintenance in time to ensure the strength of the foam concrete cushion and avoid cracks.

6. The construction environment temperature of foam concrete must be above 5°C, and construction in high temperature weather should be avoided.

Comprehensive comparative analysis

After using foamed concrete as the floor cushion of the residence, there are the following advantages compared with the original design of lightweight aggregate concrete:

(1) It reduces the load on the floor and makes the structure more secure.

(2) Enhance the sound insulation performance between floors and make the design more humane.

(3) It provides good thermal insulation performance for the plumbing pipeline in the cushion, reduces the negative impact of thermal expansion and contraction on the pipeline, and enhances the service life of the pipeline.

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