Environmental and Economic Life Cycle Assessment of Recycled Aggregates Concrete in the United Arab Emirates

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.

Shear Response of Recycled Aggregates Concrete Deep Beams Containing Steel Fibers and Web Openings

“…Although the financial and environmental aspects are beyond the scope of the current study, Table 8 shows typical quantifiable measures that could help practitioners and researchers to evaluate environmental benefits and associated costs of RC structures made with RCAs and steel fibers. The environmental impact of the alternative materials can be quantified by evaluating their global warming potential (GWP) values published in the literature [49][50][51][52][53][54]. From Table 8, it is evident that the use of RCAs along with steel fibers in replacement of NAs and conventional steel stirrups results in a significant reduction in GWP.…”

Life Cycle Assessment of Construction and Demolition Waste Management in Riyadh, Saudi Arabia

“…Similar practices have been reported for Korea, where 80% of recycled aggregates are used in backfilling ( Figure 8 a) and road construction ( Figure 8 c,d) [ 1 ]. For concrete applications, the inferior mechanical properties of recycled aggregates, in comparison to natural aggregates, the addition of steel fibers and additives (e.g., fly ash and micro silica) into the concrete mix can enhance the structural properties of concrete [ 8 , 44 , 45 ].…”

“…Kim [ 1 ] studied the present waste generation and treatment methods, government policies, and stakeholder efforts toward aggregates recycling in Korea and found a motivational drive in all these aspects of CDW management. CDW in the United Arab Emirates (UAE) accounts for 30% of the total waste, most of which is landfilled [ 7 , 8 ]. Due to inadequate recycling and reuse practices in the Kingdom of Saudi Arabia (KSA), 53 million tons per annum of municipal solid waste causes an environmental loss worth 1.3 billion dollars, whereas 30–40% of urban waste is CDW [ 9 , 10 ].…”

Bond to Bar Reinforcement of PET-Modified Concrete Containing Natural or Recycled Coarse Aggregates

“…In addition to the large amounts needed for construction, natural coarse aggregate (NCA) requires quarrying, processing, and transportation to the construction site. Replacing part of aggregate with recycled materials can offer a distinct advantage, thus reducing the number of raw materials used and plastic waste which is normally destined to landfill [16][17][18]. This would conserve natural resources and reduce the environmental impact of waste materials.…”