Influence Of Elevated Temperature On The Protective Effectiveness Of Silane Agent

Fire is one of the potential factors which can damage buildings. Once fire, the property of building materials will be deteriorated significantly, the performance of the structure will be weakened greatly and the economic losses will be very huge. Therefore, research on the fire performance is extremely urgent. Since the 1950s, a large number of experiments have been carried out on this point abroad, China began since 1980s in this area and obtained a lot of achievement. However, these studies mainly focus on the strength of concrete materials and the stability of the whole structure after fire, few research on durability loss after fire and economical, durable protection/repair technology measures was carried out.On the other hand, more and more Silane water repellent agent has been applied to protect the concrete in severe environment to improve the durability of concrete structure. But, few experiment was carried out on the fire stability of Silane water repellent agent. Based on these problems, a lot of investigation was carried out on the following aspects.(1)Residual compressive strength, residual dynamic elastic modulus, water absorptin and chloride penetration were investigated after NSC and HPC were subjected to different high temperatures and cooling regimes. Base on the results, people can assess the structure after fire, especially the durability evaluation.(2)Study the ordinary concrete and high-performance concrete in different temperature and cooling system, the remaining after the compressive strength and the rest of the dynamic elastic modulus variation, and high temperature and cooling water system of concrete performance and antichloride erosion performance impact. For fire-damaged concrete structure, especially the durability evaluation.(3)Surface impregnation by silane gel was applied to concrete exposed to elevated temperature. Then determine the penetration depth of silane gel, water absorption and chloride penetration. After that, evaluate the effect of surface impregnation from the changes of water absorption and chloride penetration.The results indicated that the use of silane gel (amount: 400g/m2) can obviously improve the water absorption of fire-exposed concrete and an effective chloride barrier can be built up. In this way, the durability of fire-exposed concrete can be improved and the service life of fire-exposed concrete can be extended. Then advice can be given on how to protect and repaie the concrete structure after fire.(4)First treat the concrete with silane gel, then the water repellent treated concrete were heated in an electric oven. From the change of water absorption and chloride penetration of water repellent treated concrete befor and after elevated temperature, we can get the fire stability of surface water repellent agent. Results indicated that when the temperatue is higher than 200℃, the silane surface water repellent agent will lose its efficiency.(5)Add silane emulsion to fresh concrete (integral water repellent concrete), then the integral water repellent concrete were heated in an electric oven. From the change of water absorption and chloride penetration of integral water repellent concrete before and after elevated temperature, we can get the fire stability of integral water repellent agent. Results indicated that when the temperatue is higher than 300℃, the integral water repellent agent will lose its efficiency.