Effects of hydrostatic pressure on chloride ion penetration into concrete

摘要

Chloride ion penetration is the main cause of steel corrosion in reinforced concrete, and significantly aggravates the degradation of concrete durability. With the development of concrete structures that are hydraulic or situated in the ocean, concrete is more often subjected to environments with high hydrostatic pressure. This paper investigates chloride ion penetration into concrete under a hydrostatic pressure environment. Fresh concrete and concretes mixed with various mineral admixtures are prepared, and the influence of the value and application time of hydrostatic pressure on chloride ion penetration is explored. Results show that hydrostatic pressure significantly increases chloride ion penetration, especially when a high hydrostatic pressure is applied. Concrete mixed with mineral admixtures possesses a better resistance to chloride ion penetration compared with fresh concrete; in particular, the improvement is more obvious when concrete is mixed with both mineral powder and fly ash. Reducing the water-to-cement ratio is an effective method to improve the resulting concrete's resistance to chloride ion penetration. Under an environment producing hydrostatic pressure, water and chloride ion penetration are not synchronous, and the water penetration depth is much higher than the chloride ion penetration depth.