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.