Fabrication and Properties of Blended Calcium Sulfoaluminate Cements Based on Thermally Treated Reservoir Sediments

In 2021, approximately 4.1 billion tonnes of cement were globally produced and the annual CO2 emissions from cement plants reached almost 2.8 billion metric tonnes. In recent years, many efforts have been made to manufacture low-CO2 cements. In this regard, great consideration has been given towards calcium sulfoaluminate (CSA) binders for both their technical features and sustainable properties, principally connected to their industrial process. The use of blended cements composed by CSA binders and supplementary cementitious materials (SCMS) can be an effective way to (a) reduce the CO2 footprint and (b) produce greener binders. This scientific work studied the utilization of different amounts (15–35 wt%) of calcined reservoir sediments (RS) as SCMS in blended CSA binders, where the binders were cured for up to 56 days and characterised by various analytical techniques. It was found that thermally treated RS were particularly noteworthy as their utilization allowed for a dilution of the CSA clinker, thus implying a decrease in CO2 emissions and a reduction in costs related to their production. However, compared to a plain CSA cement, the blended systems showed rather similar volume stability levels, whilst their compressive strength and porosity values were, respectively, lower and higher at all the investigated aging periods.