Nondestructive Testing Indicators And Durability Evaluation Methods Of Concrete Bridge Under Marine Environment Analysis

Concrete structures have been widely used in bridges across sea and river. Due to its economic losses and social impacts,structure degradation caused by environmental corrosion has been closely watched. In view of the chloride penetration resistance of concrete bridge under marine environment, especially concerning nondestructive testing at site and durability evaluation, experimental and theoretical studies were conducted.Firstly,based on backgrounds and current situations of concrete resistance to chloride ion erosion research and engineering practice of the Oujiang river bridge, influences of water-binder ratio, types and dosages of admixtures and mixing time on the chloride penetration resistance of concrete were obtained and chloride diffusion coefficient determined by PERMIT ionic migration method was selected as nondestructive testing indicator at site and control standard of this indicator was set up according to research situation,project practice and experimental research.In the second place, to make the theoretical research more close to engineering practice, a self-renewing endurance life predicting method based on contingent probability and field inspection was established based on Fick’s Second Law and reliability theory. This method takes more fully use of data from field test and combines more closely with actual conditions.After PERMIT ionic migration method and self-renewing endurance life predicting method based on contingent probability were applied to the Oujiang Bridge, reasonable predicting results were obtained. And key time nodes of durability degradation of the bridge are analyzed Example shows that, durability failure probability forecast reduced by varying degrees when data of field test of each stage was taken into account, compared with direct durability failure probability forecast. Extent of reducing relates to the probability of conditions happen.To facilitate the practical application from the respect of engineering staffs, according to the complete process of newly established self-renewal durability life prediction method, the visual interface " Durability appraising of resistance of concrete bridge in marine environment to chloride ion erosion" was established with the aid of MATLAB GUI function,which could be meliorated and consummated with actural demands.