Life cycle assessment including traffic noise: conventional vs. rubberized asphalt

Purpose: It is estimated that in Colombia around 25 million tires are disposed of yearly. The management of discarded tires is still a major problem considering that 3 of 10 disposed tires end up on sidewalks, separators, parks, wetlands, and even in front of houses. Additionally, mainly in urban and suburban zones near the main roads, noise is one of the central factors that affect people’s quality of life. In this article, a life cycle assessment (LCA) from cradle to grave of rubberized and conventional asphalt pavements was employed to quantify the consequences associated with the implementation of the alternative technology and the present engineering practices. LCA was performed involving the local materials and available machineries in Colombia, and the inclusion of traffic noise as part of the LCA. Methods: LCA in this study involves two methods: attributional LCA (ALCA) and consequential LCA (CLCA). To include the effect of traffic noise in the LCA, a methodology developed by the Swiss author Gabor Doka (2003) was used. Estimation of material’s quantities and their characteristics, noise levels, logistics, and production were done based on a Colombian case study. Results and discussion: Damage assessment showed that conventional asphalt (CA) impacts 67% more in human life than rubberized asphalt (RA). Traffic noise assessment results presented that CA has about 38% more impact in human life compared with RA, then, considering the study period (25 years), a reduction of 2.8 dB in noise emission due to the implementation of RA represents a considerable positive impact in human life. The total effect in ecosystems showed that CA has 40% more impact in the extinction rate of species than RA. In total, CA causes 43% more impact in resources than RA. Consequential assessment showed that the implementation of the RA represents 48% less environmental damage than the conventional alternative. Conclusions: RA is a more environmentally friendly alternative compared with CA because it requires less raw material usage, and less mix production due to its better performance (less maintenance and rehabilitation interventions). RA represents a suitable alternative to divert tons of used tires from the landfills.