Eco-friendly design of Warm mix asphalt (WMA) with recycled concrete aggregate (RCA): A case study from a developing country

Abstract

Warm Mix Asphalt (WMA) is a type of asphalt concrete with growing notoriety in the paving industry since they generate economic and environmental benefits compared to traditional alternatives. Various techniques have been studied to maximize the sustainability components present in WMAs, including the Recycled Concrete Aggregate (RCA) inclusion as a partial replacement for virgin aggregates. WMA with various RCA contents has been examined in several case studies from the mechanical, performance, and economic perspectives. Nonetheless, thorough environmental studies have so far been limited, mostly assuming that the use of RCA reduces the environmental burden due to being a recycled product. However, this consideration is not entirely correct since RCA increases the optimal asphalt content. Therefore, excessive RCA contents generate a counterproductive environmental effect. The difficulty associated with the estimate of how much RCA is considered detrimental could explain why detailed environmental evaluations have not been developed on this type of material. This study develops a trade-off methodology based on the Life Cycle Assessment (LCA) technique and statistical analysis to determine the maximum RCA content to be incorporated into WMA without generating greater environmental impacts. The main contributions of this investigation to the literature are establishing the first approach to optimize the design of WMA with RCA inclusion and identifying the variables that directly affect the contaminating potential of this type of asphalt mixture.