Durability characteristics of sustainable concrete with low clinker cements

In the last years, cement industry has focused on cements with low content of Portland clinker for implementing a sustainable development. The objective is the production of blended cements (CEM II) as well as composite cements (CEM IV and CEM V) with major content of mineral additions than conventional cements. Such innovative formulations could not only reduce clinker production and carbon dioxide emission, but also solve future difficulties in the supply of industrial by-products, such as slag, by replacing them with other pozzolanic additions, included calcined clay. Clay can be calcined directly in the cement factory at lower temperatures than those of clinker production. Anyway, the benefits of low-clinker cements need to be also assessed on the long-term. This note compares several low-clinker cements, produced with slag, natural pozzolana, calcined clay and limestone, and discusses their effect on concrete properties. Besides basic characterization at hardened state, also durability-related properties (such as resistance to carbonation and chlorides penetration, sorptivity, water absorption and electrical resistivity) were evaluated. Preliminary results reveal that the studied cements can play a key role in ensuring mechanical and durability performance suitable at specific degradation conditions.