1. Laitance and control measures
After the self compacting concrete is poured, more laitance is easy to appear on the surface. In order to avoid the appearance of excessive laitance, the corresponding expansion degree should be controlled according to different parts in the pouring process. If the small box girder is poured in the beam yard, the slump expansion of concrete is controlled between 690mm and 710mm when pouring the bottom slab; When pouring the roof, the slump expansion of concrete should be controlled between 670 mm and 690 mm.
2. Workability and control measures
The workability of self compacting concrete is not stable. When pouring, the workability of concrete is poor, and it is easy to appear dispersion, segregation and "false setting" phenomenon. Before concrete mixing, it is necessary to strictly control the moisture content of the tested aggregate, the temperature of the powder into the machine, and the control of the sun protection measures and transportation time of the mixing truck during the transportation.
3. Aggregate moisture content and control measures
When self compacting concrete is poured, it is often difficult to construct due to the large or small expansion, which leads to the solid quality problems of the structure. The main reason is that the moisture content in aggregate, especially in rainy weather and humid environment, changes greatly. Therefore, it is necessary to control the moisture content of aggregate through "multi inspection and multi measurement" method, so as to ensure that the concrete has good slump expansion, facilitate the construction, and ensure the quality of construction molding.