Increasing the Reuse Potential of Recycled Aggregates from Concrete and Masonry CDW: Treatment, Performance, and Sustainability for Structural Applications

Rajapaksha, ND ORCID: 0009-0003-5765-9893, Ameri Vamkani, M, Gkantou, M ORCID: 0000-0003-2494-405X, Giuntini, F ORCID: 0000-0002-3444-8183 and Brás, A ORCID: 0000-0002-6292-2073 (2026) Increasing the Reuse Potential of Recycled Aggregates from Concrete and Masonry CDW: Treatment, Performance, and Sustainability for Structural Applications. Construction Materials, 6 (3). ISSN 2673-7108

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Abstract

Recycled aggregates (RAs) from construction and demolition waste (CDW) provide substantial circular-economy benefits, yet their elevated porosity, adhered mortar, and heterogeneity typically impair the mechanical performance and durability of recycled aggregate concrete (RAC). This PRISMA 2020-compliant systematic review synthesises 2180 records (2015–2026) to evaluate advanced strategies for enhancing RA quality prior to structural use. This paper critically compares removal-based treatments (mechanical, thermal, acid cleaning) with strengthening and densification approaches, including accelerated carbonation, pozzolanic and nano-silica coatings, polymer impregnation, microbial-induced calcium carbonate precipitation (MICP), and modified mixing methods such as triple-stage mixing (TSMA). Evidence shows that while all RA types (including recycled fine aggregate (RFA), recycled coarse aggregate (RCA), and their combination (RFCA)) can slightly reduce compressive strength and 30% replacement serves as a critical threshold, beyond this, strength loss accelerates, particularly in RCA and RFCA mixes. However, accelerated carbonation and TSMA consistently refine the interfacial transition zone, reduce water absorption by 17–30%, and recover 85–94% of natural aggregate concrete strength. Bio-deposition reduces water absorption by 13–21%, while acid/silica fume treatments improve late-age strength but carry environmental trade-offs. This review formulates a practice-oriented implementation framework for structural-grade RAC. Sustainability analyses indicate that carbonated RA can achieve net-positive CO2 abatement when under low-carbon energy supply. A mechanistic schematic is presented to synthesise treatment-to-pore-structure/durability pathways across the four principal treatment routes, and a quantitative synthesis plot compares water absorption reductions across all treatment types using 13 data points drawn from included studies. A structured treatment comparison evaluates the energy intensity, industrial scalability, CO2 footprint, and technology readiness level for each strategy. The remaining challenges include a lack of hybrid treatment studies, limited real-scale durability data, and insufficient mechanistic models linking treatment to pore structure evolution. This review recommends harmonised durability-based criteria and updates to standards (e.g., BS 8500, EN 12620) to support the scalable deployment of treated RA.

Item Type:	Article
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Divisions:	Civil Engineering and Built Environment Pharmacy and Biomolecular Sciences
Publisher:	MDPI AG
Date of acceptance:	22 April 2026
Date of first compliant Open Access:	22 May 2026
Date Deposited:	22 May 2026 12:57
Last Modified:	22 May 2026 12:57
DOI or ID number:	10.3390/constrmater6030029
URI:	https://researchonline.ljmu.ac.uk/id/eprint/28619

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