A comparative environmental impact analysis of asphalt mixtures containing crumb rubber and reclaimed asphalt pavement using life cycle assessment

Abstract

Recently, the reduction of the environmental burdens related to highway infrastructures has been in the spotlight. Within this context, the use of recycled materials in bituminous mixtures for road pavement construction and maintenance has the potential to mitigate the excessive use of non-renewable resources. Nevertheless, the material consumption is only one of the aspects that affects the sustainability of an infrastructure. Other relevant aspects related to environmental issues should be considered. The objective of this work is to evaluate the potential environmental impacts of asphalt mixtures containing crumb rubber (CR) (vulcanised or devulcanised) and reclaimed asphalt pavement (RAP) assuming different Degree of binder Activation (DoA) of the aged binder by means of a life cycle assessment (LCA). The results show that the small amount of CR used for bituminous mixtures application does not justify all the additional consumption of resources and emissions associated with its treatment. These results are explained by the higher environmental impacts stemming from the treatment of the rubber and the higher amount of bitumen employed in the mixture. In turn, for mixtures containing RAP the analysis revealed an improvement in the score of all the environmental indicators considered.

Recycling waste plastics in roads: A life-cycle assessment study using primary data

“…Nevertheless, the recent common trend in the pavement industry consists of using waste materials in road pavement applications as a response to the need of both reducing the consumption of virgin and increasingly scarce materials and avoiding landfilling (Li et al, 2019;Zhao et al, 2020). In order to quantitatively evaluate the potential environmental effects of using these waste materials in road pavement applications, several Life Cycle Assessment (LCA) studies have already been conducted (Giustozzi et al, 2012;Aurangzeb et al, 2014;Santos et al, 2015;Farina et al, 2017;Santos et al, 2018;Wang et al, 2018;Bressi et al, 2019;Praticò et al, 2020;Landi et al, 2020). However, most of them relied on the use of secondary data and models rather than primary data directly sourced at the plants.…”

Evaluation of Road Infrastructure Projects: A Life Cycle Sustainability-Based Decision-Making Approach

“…A list of some recent studies related to the life cycle sustainability assessment of road projects is presented in Table 1. Studies focusing on the environmental aspects only are mainly related to pavement material selection [15,17], or pavement maintenance strategies [19,20,26]. Few other studies incorporated the economic criteria along with the environment for project evaluation [20,25].…”

Impact of Preheating Temperatures and RAP Characteristics on the Activation of RAP Binder

“…Bressi et al [8] evaluated the environmental impacts of using RAP with different degrees of binder activation (0, 20, 50, 70, 80 and 100%) by means of a life cycle assessment (LCA). With the increase of DoA, great benefits can also be seen from other impact categories (especially marine ecotoxicity, fossil fuel depletion and human toxicity).…”

“…Full-depth reclamation is a cold technique that blends the existing asphalt layer with underlying base material and stabilizing agent to produce a new base layer, while hot recycling can activate the reclaimed asphalt (RA) and apply RA pavement (RAP) to the production of surface layers. Since the less expensive RA binder can replace a portion of the more expensive virgin binder, the use of RA binder is economical and may also help to reduce a set of environmental burdens [2,7,8]. With the rapid rise of asphalt prices [9], there have been several research efforts made towards maximizing the quantity of RAP used in the production of recycled asphalt mixtures (RAM) [10][11][12][13].…”