Development of composite cements characterized by low environmental footprint

The production of cement is associated with significant CO2 emissions. The effective manner to cope with this challenge is the production of composite cements characterized by high Portland cement clinker replacement ratio. This contribution reports on the composition optimization of the ternary cement, with the purpose to maximize the cement performance evolution while minimizing its environmental impact. For this purpose, based on the understanding of the cement hydration and performance evolution, a modelling tool was developed allowing predictions of the compressive strength depending on the cement composition and curing time. The approach used accounted for the specific interactions among the Portland cement clinker, granulated blast-furnace slag and limestone and for the specific microstructure features in the investigate systems. The agreement between the predictions and performance evolution measured had confirmed the accuracy of the models developed as well as of the general concept of the composite cement optimization. Consequently, the effective global warming potential of the composite cements was calculated. This revealed that composite cements characterized by approximatively 50 wt.-% of Portland cement clinker, 40 wt.-% of granulated blast-furnace slag and 10 wt.-% of limestone are characterized by an appreciable performance and by the appreciably low environmental footprint. (C) 2019 Published by Elsevier Ltd.