The excavated materials of the future tunnel between Lyon and Turin present sulphate content higher than those recommended by current European standards. These sulphates can react with cement components and lead to damages in the concrete. Considering this specific problem and the necessity to use the excavated materials as aggregates, two studies were conducted. The first one focuses on excavated materials in order to assess the kinetic of sulphate release as a function of temperature and pH. The results highlight fast release kinetics when pH is higher than 5 and the temperature higher than 20°C. The second one focuses on the behaviour of different mortars compositions in order to reduce or cancel any damage risk for the concrete. Considering the results, some promising solutions can thus be considered.
