Abstract: In order to further improve the resistance of concrete to sulfate corrosion, under the condition of optimum mix proportion, the experiment of dry and wet corrosion and long-term immersion corrosion of concrete with different fiber content was carried out.The macro test methods such as morphology damage observation, mass loss, relative dynamic elastic modulus and compressive strength were adopted, to study the corrosion resistance of hybrid fiber concrete and its corrosion mechanism by SEM microstructure test.The results show that the concrete with different fiber content has different degree of damage under sulfate corrosion;the corrosion damage under the wet and dry cycle is more obvious than the long-term soaking corrosion.In the long-term immersion corrosion time of 450 d, the concrete has a compressive strength of 60 MPa, and the fiber concrete has a compressive strength of 70 MPa.However, in the dry and wet cycle corrosion, polyethylene fiber and polypropylene crude synthetic fiber mixed with 0.8%+1.2%, the concrete also has a compressive strength of 70 MPa.Fiber can alleviate the internal structural stress of concrete, disperse porosity, channel and other defects, as well as fiber bundles between the bridge are significantly improved the resistance to sulfate corrosion of concrete.

Key words: fiber concrete;sulfate;corrosive;dry and wet cycle;long-term immersion