Development of composite cements characterized by low environmental footprint.

The production of cement is associated with significant CO 2 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. Image 1 • Paper focuses on the composite cements containing Portland cement clinker, slag and limestone • Modelling tool was developed for predictions of the compressive strength evolution depending on initial cement composition • The model is based on the thermodynamic calculations, while the empirical models are used for the kinetics of hydration and strength predictions • Cements are ranked by their effective global warming potential • Cements containing approximatively 50% of clinker, 40% slag and 10% of limestone are characterized by good performance and by low environmental footprint [ABSTRACT FROM AUTHOR]