Self-waterproofing measures for structural concrete
In waterproof engineering, the waterproof concrete of the main body and the auxiliary structure is structurally rigid and self-waterproof, which can not only improve the crack resistance and seepage resistance of concrete, but also improve the waterproof ability and crack resistance of the whole concrete to a certain extent.
Main construction measures
The use of high-performance admixtures shrinks waterproof concrete, and controls the coarse and fine aggregates that appear in the construction to improve the overall quality of the concrete, and at the same time to ensure that the impermeability level of the concrete itself meets the relevant requirements and standards. It is necessary to strictly follow the relevant design proportions to ensure the thickness of the entire waterproof structure. After many designs and repeated tests, the pouring method is finally determined. The use of "double mixing" technology, that is, mixing superplasticizer and fly ash, can reduce the amount of cement, reduce the heat of hydration, and minimize the occurrence of shrinkage cracks. The measurement, mixing and transportation of concrete need to be monitored throughout the process. In the area where the structure is subjected to shear force, corresponding measures should be taken for the construction joints of the structure to avoid contact between the internal devices of the concrete and the formwork. During this period, no through cracks can appear.
As we all know, in the construction of subway waterproofing projects, the self-waterproofing of concrete structures is the most basic content of structural waterproofing. Among them, in the construction process, the water-cement ratio, the amount of cement and the sand rate should be strictly controlled to fundamentally ensure the quality of concrete. It is also necessary to add water reducer or expansion agent in time to enhance the crack resistance of concrete when the shrinkage rate of concrete is reduced. Generally, when adding cement, cement needs to add 300 kg/m3. In order to improve the workability of concrete, it is necessary to appropriately reduce the water-cement ratio, add a water-reducing agent, and control the dosage to about 0.9%. When selecting aggregates, the diameter should be less than 4cm, and the gradation should be good, and the void volume between the aggregates should be reduced. Choose medium sand, the mud content should not exceed 3%, the sand ratio should be around 40%, and the ratio of lime to sand should be between 1:2 and 1:3. It is necessary to ensure that the collapse rate of the pumped concrete is less than 15cm. When controlling the construction process of concrete, the mixture needs to be filled in the whole model to ensure the integrity and uniformity of the mixture. Segregation does not occur. The steel bars inside the concrete should not touch the formwork, and the formwork should be stable. Before construction, use cement mortar of the same grade and strength to lubricate the pipes. When the pump is sent into the mold, it should be symmetrical to the left and right to achieve continuous pouring.