Hybrid binders: A journey from the past to a sustainable future (opus caementicium futurum)

Abstract

This article describes and interprets data drawn from a thorough characterisation of a series of cementitious materials. The materials addressed can be divided into three major groups: 1) cements/concretes from well-known and historically documented Roman constructions in Italy; 2) cements recently prepared in the laboratory simulating the compositions of Roman cements, stored for 6 months in environmental conditions similar to those to which the Roman materials have been exposed for 2000 years; 3) concretes prepared from an industrial cement manufactured 6 years ago applying today's knowledge of hybrid cements. An analysis of all the data presented in this article has led its authors to conclude that, conceptually speaking, ancient Roman cements can be identified with modern hybrid 'portland-alkaline' materials. That conceptual identity is based on the detection of the same cementitious phases in the two types of cements (Roman and Hybrid) and naturally of the inclusion of alkalis in the structures of some of the phases observed.