**Preface to "Supplementary Cementitious Materials in Concrete"**

The substitution strategy, consisting of the partial replacement of Portland cement with supplementary cementitious materials (SCMs), or the more common application of blended cements, is an effective way to improve the sustainability of the construction industries. In fact, they foster the introduction of new and more environmentally friendly construction materials, with improved physical and mechanical properties, to be used in building engineering. Therefore, various research issues regarding SCMs are herein considered and described in detail through both research papers and state-of-the art reviews.

**Alessandro P. Fantilli, Daria J ´ozwiak-Nied ´ zwiedzka ´**

*Editors*
