A critical review of untreated waste concrete powder as a supplementary cementitious material for mortar production

The decarbonization of cementitious materials has intensified interest in waste-derived supplementary cementitious materials, particularly waste concrete powder (WCP) obtained from construction and demolition waste. This review provides a critical synthesis of WCP-incorporated mortars from an integrated environmental-mechanical-economic-performance framework perspective. Existing studies consistently demonstrate that WCP incorporation in cement mortars significantly reduces carbon dioxide emissions and lower production costs. However, increasing WCP content is generally associated with a decline in mechanical, durability, and physical properties, highlighting a fundamental trade-off between environmental-economic gains and structural reliability. To address this challenge, this review study advances a conceptual triple-axis sustainability-performance framework, in which environmental impact reduction, mechanical-durability performance, and economic efficiency are evaluated as interdependent design considerations within a unified multi-objective qualitative space. In addition, a performance-based classification framework is proposed to guide the practical application of WCP-based mortars under varying performance requirements. The review further identifies key research gaps, including the need for performance-normalized life cycle assessment, integrated life-cycle cost analysis, and region-specific techno-economic evaluation of WCPs. Overall, the findings suggest that WCP offers a viable pathway toward circular cementitious systems when implemented within optimized substitution regimes that balance environmental, structural, and economic considerations.