High-Performance Concrete with Treated Recycled Coarse Aggregate: A Performance-Gated Critical Review

Abstract

Recycled Coarse Aggregate (RCA) can reduce virgin aggregate demand and divert demolition waste. Still, its use in High-Performance Concrete (HPC) is constrained by adhered old mortar, source heterogeneity, high water absorption, microcracking, and multiple interfacial transition zones. This critical review synthesizes evidence on RCA quality, fresh behavior, mechanical response, transport-controlled durability, treatment technologies, and life-cycle performance using a strengthened structured-review protocol. The thesis-derived source set was updated and verified through 11 August 2026, yielding 22 core sources spanning RCA/HPC behavior, treatment and durability, life-cycle assessment, and governing standards. Experimental treatment evidence was used quantitatively only when treated and untreated RCA were compared at the same replacement level, or when the source reported a directly normalized change; incompatible mixture conditions and test methods were not statistically pooled. Reported effects demonstrate substantial but method-specific variability. Autogenous cleaning has reduced adhered mortar by about 50%, lowered water absorption by 20%–50%, and increased density by 3%–16%. Accelerated carbonation has produced a 22.6% increase in 28-day compressive strength in the cited pressure study, while cyclic carbonation studies report gains of about 25.2% in compressive strength and 26.5% in flexural strength. Nano-silica treatment has produced approximately 20%–25% compressive-strength gains, and optimized bio-mineralization has reduced aggregate water absorption by about 15%. These benefits are not universal: high-temperature removal can impose large energy burdens and has produced strength loss in some studies, while acid treatments may improve absorption and compression yet reduce flexural performance and create effluent. To translate the evidence into practice, the review operationalizes a non-compensatory performance-gated framework. Absolute project and code requirements take precedence; for the M60-class context, the 28-day characteristic compressive-strength requirement is at least 60 MPa. Where no codified limit exists, a provisional paired screening criterion of at least 0.90 retention for higher-is-better responses and no more than a 1.10 ratio for lower-is-better transport or damage indicators is proposed. Sustainability and cost is evaluated only after all mandatory technical gates pass.