Mechanical and environmental assessment of mortars with high coal-bottom ash replacement from local industry

Here, we evaluate the replacement of Portland cement in mortars with coal bottom ash waste from the local industry. We replaced up to 45 % of the cement in the mortars and obtained a compressive strength of 34.5 and 22.7 MPa at 28 days for 5 % and 45 % replacement, respectively. Simultaneously, we report the flow spread variations during the specimen preparation and relate those results to the chemical characterization by DRIFT, Raman, XRD, XRF, and SEM-EDS to demonstrate the formation of aluminosilicate gels. Finally, we present a Life Cycle Assessment for the materials obtained and demonstrate a reduction in CO2 equivalent emissions of up to 34 % due to 45 % OPC substitution. The additional materials processing and transportation for the highly replaced mortars contribute up to 9 % of the emissions. All these results while retaining the material feasibility for heavy loads, retaining walls, or driveway mortar applications.