Innovative solutions for the use of high sulfate content materials as aggregates for concrete

Within the framework of the future railway link between Lyon (France) and Turin (Italy), it is proposed to use the highest part as possible of tunnel excavated materials as concrete aggregates. This objective will permit to prevent the excavation of new quarries, to limit the transport by road of excavated materials, and to avoid their definitive storage. Nevertheless, these excavated materials contain higher amounts of sulphates than those recommended by standards. The studies carried out leads to consider that several solutions can be proposed as washing materials before use, choosing appropriate cement, or using the excavated materials as a source of sulphates to control cement hydration.