Experimental Studies On Steel Corrosion In Concrete Structures And The Caculation Method Of Durability In Marine Environment

Reinforced concrete structures are widely used in coastal engineerings,durability of reinforced concrete structures under marine environmental has becomea very serious problem that we must face when design and maintain coastalengineering structures. Combining with domestic and foreign literatures, the maindurability disease of RC structures is steel corrosion caused by chloride diffusion. Atpresent, most researches according to chloride diffusion under marine environmentaldon’t consider load factors; most researches on steel corrosion are qualitative studyand the existing rebar corrosion-rate models are quite different.Based on the results of previous studies, by chlorine diffusion experiment inloaded concrete under marine environment and the indoor accelerated corrosionexperiment by mixing sodium chloride inside, chloride diffusion model consideringload factors and indoor accelerated rebar corrosion-rate models are summarized.Correlation between indoor accelerated environment and field environment ispreliminary established. Use the results to improve the system of assessing thelife-span of the durability. Evaluate and predict life of an open type wharf by anexample. The main works are as follows.1. By chlorine diffusion experiment in loaded concrete in inside simulated saltspray zone and tidal zone, discuss how to decide the value of surface chlorideconcentration, analyse the load effect to the chloride ion diffusion coefficient.Chloride diffusion models considering load factors in salt spray zone and in tidalzone are established.2. Based on accelerated corrosion experiment by mixing sodium chloride inside,research on the relationship among the steel corrosion rate, time and chloridecontent．Rebar corrosion rate model in a typical indoor environment are fitted outexperimentally and the model is verified by experimental data.3. Introduce the multi-environmental time similarity theory (METS).Correlation between the field inspection data and the results of indoor experiments ispreliminary established based on METS.4. Calculate reliability of RC structures under marine environment based on JC method. According to serviceability limit state, analyse reliability, then evaluate andpredict life of slab, beam and pile of an open type wharf by an example.