Durability of blended cements containing sulfoaluminate clinker

The cement industry is strongly committed to a very ambitious "zero emission"trajectory maintaining the highest level of quality and durability performances. Zero emission target will be reached using several leverages, including the reduction of the clinker content in cement. Low clinker cement represent a market solution and are already efficiently implemented in many European countries, however, the strength development of low clinker cement at early age is lower compared to Ordinary Portland Cements (OPC) with higher clinker contents. The use of blends of low clinker Portland cement and Calcium Sulfoaluminate Cement (CSA) could support the need for low CO2 binder with high early strength. The behavior of four blended cements containing CSA clinker, OPC clinker, limestone, fly ash, pozzolana and slag has been characterized using different techniques in terms of resistance to carbonation, chloride migration and sulfate attack. The findings indicate that the durability performances are enhanced when supplementary cementitious materials (SCMs) with pozzolanic or latent hydraulic activity are present, as opposed to the presence of limestone. SCMs exhibit an active role also in an OPC-CSA matrix. Blend of CSA-OPC cement and slag represents a system characterized by both high early and late strengths, along with favorable durability behavior.