Predictive models for strength properties of sustainable mortars containing waste concrete powder: an empirical approach

Waste concrete powder (WCP), obtained from discarded concrete, was used as a fractional substitute for cement in mortar production. During mortar preparation, cement was partially replaced with WCP at intervals of 10%, ranging from 0 to 30%. The obtained results showed that increasing the WCP level led to a considerable reduction in mechanical properties of the mortars. For instance, replacing 30% of the cement with WCP led to a reduction in the control mortar’s compressive strength from 40 N/mm² to 30 N/mm² over a 28-day period. However, the mortars still met the strength required for masonry applications. Also, predictive models were developed using the experimental data to estimate the compressive and flexural strengths of WCP mortars. The developed models’ effectiveness was assessed using experimental data gathered from published studies. The proposed models make it feasible to change conventional mortars’ standard strength grades into equivalent values for WCP-based mortars. Hence, the models can be effectively applied for practical predictions, as well as for the design and analysis of sustainable mortars incorporating WCP.