PSI - Issue 64

Rahma Dhemaied et al. / Procedia Structural Integrity 64 (2024) 343–351 Rahma Dhemaied/ Structural Integrity Procedia 00 (2019) 000 – 000

348

6

6. Cost analysis of recycled concrete aggregates in pavements 6.1. Material comparison

Different studies found that recycled concrete aggregates (RCA) were 10-20% less expensive on average compared to natural aggregates (NA) for pavement applications. The exact cost difference depended on factors like transportation distance, processing requirements, and regional material availability. A study by (Wang et al., 2020) in a region with limited NA supplies reported RCA costs 15-25% lower than NA. Conversely, a paper by (Li et al., 2019) in an area with abundant NA sources found the cost gap to be closer to 19-40%. Overall, the literature indicates RCA can provide notable material cost savings, especially in regions with constraints on natural aggregate resources. When accounting for the full construction costs, including material, placement, compaction, and other factors, the research found that the use of RCA resulted in 5-12% lower total pavement construction costs compared to NA. Although RCA pavement sections had similar or slightly higher initial construction costs, the material cost savings were able to offset this. A study by (Zhang et al., 2019) reported a 7% reduction in total construction costs, while (Tam et al., 2008) found up to a 12% cost advantage for RCA. These findings demonstrate the economic benefits of RCA extend beyond just material expenses. 6.3. Life cycle cost analysis The research also considered the life-cycle costs of RCA and NA pavements over a 30-year period. It was found that the use of RCA provided 8-15% lower total life-cycle costs compared to NA pavements. This included considerations for maintenance, rehabilitation, and end-of-life recycling or disposal. A study by (Huang et al., 2018) reported a 12% reduction in life-cycle costs, while (Ding et al., 2016) found up to a 15% advantage for RCA. These findings suggest the economic benefits of RCA extend beyond initial construction and can lead to significant long term cost savings. 6.4. Regional considerations The research also found that the cost advantages of using RCA were more pronounced in regions with limited natural aggregate resources or high aggregate transportation costs. In areas with ample NA supplies and low transportation costs, the cost difference was smaller, but RCA still provided a slight economic benefit. A study by (Yeheyis et al., 2013) found a 7% advantage in a region with sufficient NA availability. Additional studies by (Evangelista and De Brito, 2007) and (Ulsen et al., 2013) have also highlighted the regional variations in the cost effectiveness of RCA. 7. Environmental impacts 7.1. Life-Cycle Environmental Impacts Beyond the construction phase, the use of RCA in pavements has been shown to provide long-term environmental benefits through reduced life-cycle impacts. (Akhtar and Sarmah, 2018) conducted a comprehensive life-cycle assessment and found that RCA pavement sections had 12-18% lower greenhouse gas emissions and 15 22% less cumulative energy demand over a 50-year lifespan compared to NA pavements. This is attributed to the reduced material extraction, processing, and transportation requirements for recycled aggregates, as well as the potential for recycling the pavement at the end of its service life. Similarly, (Braga et al., 2017) reported 10-15% reductions in global warming potential and abiotic resource depletion when substituting RCA for NA in road construction. 6.2. Construction cost