The development of a low carbon binder produced from the ternary blending of cement, ground granulated blast furnace slag and high calcium fly ash: An experimental and statistical approach

This research aims to develop a new, environmentally friendly, cementitious material by blending Ordinary Portland Cement (OPC), Ground Granulated Blast Furnace Slag (GGBS) and High Calcium Fly Ash (HCFA). Compressive strength and electrical resistivity tests were used to evaluate the mortars' performance. A multi-regression (MR) model was also utilised to study the effects of curing time and content of OPC, GGBS and HCFA on the mortars' strength and to identify the relationship between measured and predicted compressive strengths. The results indicated that the newly developed binder was composed of 35 wt% OPC, 35 wt% GGBS and 30 wt% HCFA that showed a compressive strength and surface electrical resistivity of 30.8 MPa and 103.5 kΩ.cm after 56 days of curing, respectively. Significant changes in the microstructure of the developed binder paste over curing time were evidenced by SEM imaging. The statistical analysis indicated that the influence of the parameters examined on the development of the mortars' compressive strength could be modelled with a coefficient of determination, R2 of 0.893, and that the relative importance of these parameters followed the order curing time (t)  > HCFA% > OPC% > GGBS%. This new binder could contribute significantly to decreasing the cost of construction materials and to reducing CO2 emissions.