European natural cements - their key technical properties under standardised conditions

The first comparative study on 7 commercially available Roman cements has been undertaken. In the absence of a European Standard, the testing procedures have followed a protocol proposed by the EU FP7 funded ROCARE project, which itself is based upon various ENs for cement and building limes. Evaluation has been made of mineralogy, particle size distribution, setting time, strength, water absorption, pore size distribution and mortar microstructure. Five of the cements required retardation and citric acid was used. The use of a pre-hydration technique was also investigated to extend the workable life of mortars to some 2 hours. The results confirm the view that the term Roman cement refers to a broad family of cements with a diverse range of properties which will need to be accounted for in future work to produce an all-encompassing Standard.