Deterioration of concrete in railway tunnel suffering from sulfate attack

For the sake of understanding the deterioration behavior of concrete in actual railway tunnel structures subjected to aggressive sulfate medium in practice, detailed field investigations and tested analysis on sprayed concrete linings of approximately 40-year-old railway tunnels in environments containing sulfate ion were carried out, respectively. The results show that the deterioration of concretes in the investigated area is serious, which involves complicated physicochemical process between the sulfate salt and concrete. Among them, the secondary sulfate minerals such as gypsum formation under very high concentration sulfate ion condition by accumulating and evaporation process dominate, followed by the crystallization of sulfate salt and formation of thaumasite.