The physical and mechanical properties of composite cements manufactured with calcareous and clayey Greek diatomite mixtures

The aim of the present study is to test diatomite rocks as alternative pozzolanic materials that could be used for the manufacturing of pozzolanic cements in Greece. The diatomite rocks used occur in Samos Island and in the Elassona, Greece. The Samos diatomites were mainly consisted of calcite and opal-A, whereas the Elassona diatomite consisted of opal-A, clay minerals, feldspars and quartz. As a result, the Samos samples were rich in CaO and SiO2, while the Elassona ones were rich in SiO2, Al2O3 and Fe2O3. The specific surface of the laboratory-produced cements was high, with the grindability of the Elassona diatomites being lower than that of Samos. The water demand of all blended cements was higher than that of the laboratory produced OPC. The late compressive strength of most diatomite cements studied was improved with respect to the lab OPC.