AUT Journal of Civil Engineering

AUT Journal of Civil Engineering

Enhancing Construction Sustainability through the Use of Recycled Aggregates in Concrete Production

Document Type : Research Article

Authors
Mehrdad Khoshoei 1
Khalegh Barati 2
1 Faculty of Engineering, University of Kashan, Kashan, Iran
2 School of Civil and Environmental Engineering, University of New South Wales, Australia
10.22060/ajce.2025.24090.5916
Abstract
The construction industry is a major consumer of natural resources and a significant contributor to environmental degradation, necessitating a shift towards more sustainable practices. This study comprehensively evaluates the emergy performance of concrete produced with recycled aggregates as a substitute for natural aggregates, with the aim of quantifying its potential to reduce total resource consumption and enhance sustainability within the built environment. A robust solar emergy accounting method was applied to quantify and compare all emergy inputs associated with the entire life cycle, including material extraction, processing, transportation, and the concrete production phase itself. The results clearly indicate that replacing 50% of natural coarse aggregates with recycled alternatives leads to a substantial 24.3% reduction in total emergy consumption and a 12.6% improvement in the Emergy Sustainability Index (ESI) compared to conventional natural aggregate concrete (NAC). The majority of these emergy savings are directly attributed to the avoidance of energy-intensive quarry extraction and the significantly reduced processing requirements for recycled materials. A sensitivity analysis further confirmed that the emergy advantage of recycled aggregate concrete remains significant even with increased transportation distances. These findings conclusively demonstrate that the strategic use of recycled aggregates can significantly improve the environmental performance of concrete by reducing its pressure on natural capital. This supports the transition toward more circular and resource-efficient construction practices. The study provides critical new insights and quantitative data for policymakers and industry stakeholders, highlighting the substantial emergy benefits of material substitution and informing strategies for sustainable concrete production.
Keywords
Sustainable Construction
NAC
RAC
Energy
Concrete
Subjects
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AUT Journal of Civil Engineering
Volume 9, Issue 4
Autumn 2025
Pages 325-336