Quality Control of Concrete in Spring and Autumn

2 Key Points
1.2.1 Material Control
Strengthen the quality control of raw materials, strictly control the mud content of sand and stone materials, and increase the detection and use of admixtures. Because the temperature changes greatly in this season and the strength of concrete increases abnormally, the use of admixtures should be reduced as much as possible. Put an end to the use of unqualified raw materials. The use of admixtures should be adjusted more. The admixtures have a great impact on the performance of concrete. High or low temperature makes the setting time of concrete different day and night.
1.2.2 Mix ratio control
Strictly control the water-cement ratio and reduce the amount of admixtures and admixtures. Increase the amount of cement and water to ensure that the water-cement ratio remains unchanged, and reduce the amount of admixture to prevent abnormalities during coagulation. The slump can ensure the construction performance on site, and the slump cannot be increased blindly.
1.2.3 Construction site control
Ensure that the concrete is used up immediately within 1 to 1.5 hours to prevent the slump loss and change due to long waiting time and affect the quality of the concrete. For any concrete that enters the construction site, it is strictly forbidden to add water to the mixer truck pump without permission, and it is even more necessary to prevent the behavior of adding water while constructing on the pouring surface.

Immediately after the concrete is poured, it should be leveled immediately, and before the initial setting, the finishing should be carried out no less than twice. After the finishing, the surface should be covered with film, straw bags, etc., and curing agent should be sprinkled if necessary. When using a polishing machine to finish the floor, it should be done before and after the initial setting, and the machine should not be used after the final setting, otherwise, due to the low strength of the concrete, microcracks caused by vibration are prone to occur, and the cracks are not easy to heal.

After the beam slab (floor) concrete is poured, it is forbidden to apply force too early. The hoisting materials should be placed lightly and dispersedly. vibration, otherwise it will affect the floor to produce destructive cracks.