Research and application of anticorrosive concrete for shafts in thick and deep surface soil

Abstract

Most frozen shafts of deep surface layer are located at a harsh environment, surrounding soil or groundwater with lots of corrosive ions such as SO4− and Cl−. This is deadly to the durability of concrete. Thus, concrete for shafts in deep surface soil requires excellent durability. This paper focuses on the development and preparation of anticorrosive concrete in deep surface layer shafts, and presents engineering application. The experimental results show that NC-H admixture is successfully made to prepare the concrete. The durability and impermeability of concrete are good. The Cl− diffusion coefficient of C60 is 38.1×10−14m2/s, while C90 is only 4.5×10−14m2/s. Besides, high freezing and thawing resistance is discovered. The loss of dynamic elastic modulus of C75 is less than 6.38% when the freeze-thaw cycle is 1000 times, It has high anti-sulfate ability and no corrosion to steel bar. This anticorrosive concrete has applied in many large coal mining projects. It is proved that this anticorrosive concrete has been applied to practical engineering application, and it can completely meet the requirements of cast-in-situ reinforced concrete shaft construction with deep surface layer and corrosion resistance.