The solution of bubble on concrete construction surface

1. Strengthen control of admixture and water-binder ratio
In order to solve the surface bubble problem of concrete construction, in the construction design must strengthen the admixture and water-binder ratio control, combined with the concrete construction site specific situation, on the one hand to meet the slump and stability of concrete, on the other hand, appropriate to reduce the water-binder ratio. At the same time, according to the concrete construction standards, strict control of air entraining agent content, choose the appropriate admixture, for C60, C50 high strength silicate concrete, concrete gas content must be less than 3%, for ordinary concrete, its gas content must be less than 4%, as far as possible to reduce the bubble of concrete construction.
2. Concrete transportation management
Mixing time is not reasonable. Mixing time is too short will make commercial concrete mixing uneven, bubble distribution and density is different. The test shows that under the same conditions, when the mixing time is about 3min, the bubble distribution in commercial concrete reaches uniform. However, with the increase of mixing time, the introduction of air bubbles in commercial concrete will increase. When the mixing time is about 12min, the gas content of commercial concrete reaches the maximum. Continue mixing, the gas content of commercial concrete will gradually decrease. If the transportation time is short, the mixing of the commercial concrete by the commercial concrete tanker will also introduce air bubbles. If the transportation process is long or the tank truck mixing speed is fast, the gas content loss of the commercial concrete after arriving at the scene is serious, resulting in greater slump loss. In order to ensure the stability of commercial concrete, the construction is often carried out secondary feeding mixing, which will introduce a lot of gas, so that the surface of commercial concrete formed bubbles.