RESEARCH ON CHLORIDE PENETRATION RESISTANCE AND EFFECT OF WATER REPELLENT TREATMENT OF CONCRETE AFTER FIRE

High temperature of fire hazard does have great harm to the safety, suitability and durability of concrete structures. Nowadays, more and more researchers are paying attention to the durability of concrete structures after high temperature. In this paper, autocontrolling high temperature resistance furnace is employed for simulating the fire hazard test. The changes of mechanical and chloride resisting properties of concrete are studied. And the effect of water repellent treatment of concrete surface after high temperature is discovered too. In this test, silane gel is used for water repellent of concrete after high temperature. Results show that the temperature is higher the chloride permeability of concrete is lower in the salt fog environment. Durability of concrete is affected more obviously by high temperature than strength does. However, if concrete structures could be treated appropriately using silane water repellent agent after high temperature of fire hazard, their capability of anti-chloride penetration can be improved effectively and their residual service life can be prolonged.