Re-Use of Natural Clayey Waste as Supplementary Cementitious Material.

In 2015 total world cement manufacture was estimated at 4.6 billion tons and the CO₂ emissions from cement plants were equal to approximately 3.7 billion metric tons, representing about 7% of the global anthropogenic emissions. The utilization of innovative cements and/or supplementary cementitious materials (SCMs) represent a powerful tool for both reducing the CO₂ footprint and producing more durable environmentally friendly materials. This paper investigates the possibility of using clayey reservoir sediments (RSs) calcined at 830°C as SCMs in a blended Portland cement; this binder, together with a reference one containing natural pozzolan, was submitted to hydration and mechanical tests for curing times ranging from 2 to 56 days. It has been found that RSs are very interesting SCMs inasmuch as their utilization, allowing a clinker dilution, leads to both CO₂ emission decrease and energy saving; furthermore, the hydration behaviour and the mechanical properties of the blended cement were positively affected by the RSs addition. [ABSTRACT FROM AUTHOR]