Chloride ion transport performance of lining concrete under coupling the action of flowing groundwater and loading

Abstract

In this study, the chloride ion transport behavior of lining concrete under the coupling action of flowing groundwater and loading is investigated. The results indicate that the damage layer thickness and chloride ion concentration of the lining concrete increases with the increase of erosion age. The flowing groundwater accelerates the dissolution of the lining concrete, alkaline substances such as CH and NaOH in the lining concrete dissolve out. Under the action of the loading, the micro-cracks in the tension zone of the lining concrete continue to expand and the pores are connected to each other. Therefore, for same erosion age and distance from the lining concrete surface, the chloride ion concentration in the tensile zone is the highest under the coupling action of flowing groundwater and loading; that is followed by the action of flowing groundwater alone, and then, by the action of static groundwater. The chloride ion concentration in the pressure zone is the lowest, and the addition of fly ash and silica fume is found to help in decreasing the total chloride ion concentration and increasing the bound chloride ion concentration. In this study, a chloride ion transport model is established considering the accelerated dissolution of flowing groundwater, damage caused by loading in terms of micro-cracks and pore structure, and the effect of bound chloride ion on the total chloride ion transport, further, the rationality of the model is verified.