Preparation and Application of Ordinary-Strength High-Durability Underwater-Anti-Separation Concrete in Marine Environment

The marine environment is harsh and complex, and coastal buildings are prone to deterioration under the combined action of physical and chemical destruction factors. In this paper, concrete with ordinary strength, high durability and underwater separation resistance was prepared based on the marine environment in Phase I project of Jingtang, Shougang in Caofeidian of Tangshan. The cementitious material system was optimized by adding ground slag and fly ash to improve the strength, compactness and durability of concrete. The mixture of anti-corrosion rust-resistance high-performance water-proof agent and appropriate amount of air entrainment agent improve the corrosion resistance and frost resistance of concrete, and improve the separation resistance of C35F300 underwater concrete. The results showed that the slump of concrete was 210 mm, the gas content was 5.4%, the compressive strength was 50.6 MPa, and the chloride ion erosion coefficient was 2.6×10^-12 m²/s, fully met the requirements of C35F300 (300 freeze-thaw cydes and C35 strength grade). Through engineering practice, the working performance, mechanical properties, anti-separation performance and durability of concrete could meet the requirements of concrete of underwater structures.