The application and quality control of foamed concrete in roof insulation of building engineering

2019-06-20 13:44:57

Introduction to foaming concrete

Foaming concrete, also known as foaming cement, cellular lightweight concrete,light concrete,lightweight foam concrete, etc. It is a kind of multi-functional building material made by following steps: use special raw materials made of foam by mechanical method; and then the foam has been made into the cementitious material slurry. In other words, the mix of concrete is made after full mixing, pouring molding, maintenance.

 

Application scope and properties of foamed concrete

Foamed concrete is often used in roofing and foundation pit filling and roofing thermal insulation. Compared with traditional concrete, foamed concrete has the characteristics of light weight and small density on the basis of heat preservation and sound insulation.

 

Introduction of foam concrete construction technology

1. Materials being used :(1) the water for foamed concrete should meet the requirements of national standards (jgj63-89) such as the standard for water for concrete mixing. (2) the cement is slag Portland cement with strength grade 42.5 and second-level fly ash. (3) foaming agent. Foamed concrete through the foaming system of the foaming machine, the foaming agent will be fully foaming, is a polymer with thermal polymer surfactant as organic cement.

 

2. Construction method: according to the production process and test of foamed concrete, the corresponding proportion can be used to configure the foamed slurry. Mix the cement slurry. According to the type of foam concrete selected by design, mix the weighed additive such as cement into the mixer with fixed amount of water, and keep the mixing time above 2min. The mixer mixes the pre-generated foam and pours it into the cement slurry for about 6min to ensure that the cement foam slurry is homogeneous, and then it can be poured.

 

3. Construction technology: grassroots treatment: the foundation layout board must be clean, no large area of empty drum, loose. Put an end to the foundation layout loose phenomenon. Pouring and pounding foamed concrete: ensure that the location of reserved holes in foamed concrete is accurate, and the placement of embedded parts conforms to the requirements of the drawings. It is strictly forbidden to adjust the position of reserved holes in the heat insulation layer after the initial setting of concrete, or even to re-process reserved holes. According to the thickness of insulation layer required by construction drawings, determine the elevation position of concrete pouring surface before pouring. If slope is required, adjust the elevation line and slope alignment in advance. When the construction of foam concrete insulation layer is completed, the level, dry density and thickness of roof foam concrete should meet the construction drawings and corresponding technical standards. Post-pouring treatment. After concrete pouring, pay attention to whether the sinking speed of concrete surface is uniform and whether the sinking height is abnormal, and record the data for reference. If the sinking height of concrete is large and exceeds the expected data requirements, add concrete to the required height in time and find out the reason.

 

4. Construction points: set elevation control points (3m/ point) according to the requirements of construction drawings. The elevation points must be rechecked before pouring, and set corresponding control lines according to the elevation control. When mixing foamed concrete, water should be first and material after mixing evenly, otherwise it is strictly prohibited to transport to the construction surface. Divide the working surface and set up construction joints. Ensure that the concrete in the single construction joints is cast in place at one time. It is forbidden to cast multiple times in batches. When surface construction, use long ruler rod to scrape flat, the length is not less than 3m. After completion of construction, pay attention to the maintenance of concrete, and it is not suitable for people or stacking materials within 36h. When the construction temperature is low, the time can be extended.

 

 

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