大体及防水混凝土的施工（General and construction of waterproof concrete）.docVIP

大体及防水混凝土的施工（General and construction of waterproof concrete） This project uses the underground waterproof concrete strength C35 impermeability grade S8. The thickness of raft foundation is 1.5 meters, is the large volume concrete pouring water, the construction technology requirements are relatively high, especially in the construction to prevent concrete due to hydration heat caused by the temperature difference is too large to produce temperature crack. The construction should be carefully considered, each link in the strict control, to ensure the smooth construction of mass concrete foundation slab. 1 preparatory work, construction 1.1 material selection (1): cement heat of hydration of Portland cement is considered high, especially applied to the large volume of concrete, large amount of cement hydration heat is not easy to radiate in the concrete internal temperature is too high, and the concrete surface will produce large temperature difference, concrete compressive stress produced in the surface to produce tensile stress. When the surface tensile stress exceeds the tensile strength of concrete early will produce temperature crack, it is proposed to use slag Portland cement hydration heat low, performance by adding appropriate additives can improve the concrete, improve the impermeability of concrete. Such as the use of ordinary portland cement, in order to reduce the amount of cement, reduce the hydration heat, should use high strength cement, for not less than PO42.5. (2): the coarse aggregate gravel mine machine nibbling its strength, should comply with the relevant requirements, mud content is less than 1%. The stone size is larger, with good gradation of concrete, workability is good, high compressive strength, and can reduce the consumption of water and the amount of cement, so as to reduce the heat of hydration of cement, reduce the concrete temperature rise. The concrete mix ratio by laboratory test with post to determine the best grading scheme with o