Study of performance and microstructure of sea sand on ripe pile concrete

This paper mainly studies the effects of fine aggregate which take sea sand replacing some or all river sand on the pipe pile concrete. In the experiment, making concrete specimens with sea sand mixing amount of 50%, 60%, 70%, 80%, 90% and 100% as fine aggregate, curing the specimens in accordance with pipe, then testing the strength and chloride diffusion coefficient, meanwhile, analyzing the microscopic mechanism by mercury injection test and SEM. The results show that the effects of sea sand mixing amount on strength and durability of pipe pile concrete is little; when the mixing amount of sea sand reaches 90%, the strength and anti-permeability is the best which respectively were 86.3MPa and 144×10^-14m²/s. The mercury injection test indicates that tobermorite was produced in the internal-structure of pipe pile concrete and none Cl^- exsited which further verified that the increasing of sea sand mixing amount did not influence the strength and durability of pipe pile concrete obviously and which also provided possibilities for large mixing amount application of sea sand.