Abstract
This paper studies the potential environmental and economic impact of replacing natural aggregates (NA) with recycled aggregates (RA) in the production of different sustainable concrete mixes in the United Arab Emirates (UAE). A life cycle assessment (LCA) was carried out according to the methodology proposed by the international standards of the series ISO 14040. The performance of concrete mixes having a similar design compressive strength was evaluated. Results showed that the inclusion of steel fibers (SF) led to an increase in the global warming potential (GWP), whereas mixes with cement replacement by fly ash, slag, or microsilica recorded a reduction in GWP. Furthermore, SF-reinforced mixes created with 100% RA were at least three times more expensive than the NA-based control mix, while the cost of those with cement replacement by mineral additives was generally similar to that of the control. Material transportation was found to be a main contributor to the environmental and economic impacts, only second to cement, and its contribution increased with longer distances and steel fiber incorporation and decreased with RA replacement. To integrate these individual measures and select optimum mixes for various applications, multifunctional performance indices were developed. Research findings highlight the possibility to fully replace NA with RA (100%) while maintaining the performance and improving the economic and environmental impacts of concrete produced in the UAE.
Highlights
In the past few decades, construction activities have escalated worldwide due to the increase in urban populations and the quick and extensive urbanization process [1].Despite its tremendous benefits, the construction industry is considered one of the main contributors to environmental degradation, with an ever-increasing demand for both natural resources and energy
The workability of the concrete mixes created with different proportions of recycled aggregates (RA), steel fibers (SF)
Results showed that the slump values decreased as the replacement percentage of natural aggregates (NA) with RA increased, owing to the rough surface texture and irregular geometric shape of RA [34,75,76]
Summary
In the past few decades, construction activities have escalated worldwide due to the increase in urban populations and the quick and extensive urbanization process [1]. The construction industry is considered one of the main contributors to environmental degradation, with an ever-increasing demand for both natural resources and energy. Almost 3 billion tons of raw materials are used for the manufacturing of construction materials worldwide [2,3,4]. Construction activities generate massive amounts of demolition waste. The construction and demolition waste (CDW) accounts for 35% of the total solid wastes produced around the world [1,3]. In 2016, CDW accounted for 36% of the total solid waste generation in Europe [5], while, in
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