Application of recycled crushed glass in road pavements and pipeline bedding: An integrated environmental evaluation using LCA

Quddus Tushar; Safoura Salehi; Joao Santos; Guomin Zhang; Muhammed A Bhuiyan; Mehrdad Arashpour; Filippo Giustozzi

doi:10.1016/j.scitotenv.2023.163488

Application of recycled crushed glass in road pavements and pipeline bedding: An integrated environmental evaluation using LCA

Sci Total Environ. 2023 Jul 10:881:163488. doi: 10.1016/j.scitotenv.2023.163488. Epub 2023 Apr 15.

Authors

Quddus Tushar¹, Safoura Salehi², Joao Santos³, Guomin Zhang¹, Muhammed A Bhuiyan¹, Mehrdad Arashpour², Filippo Giustozzi⁴

Affiliations

¹ Civil and Infrastructure Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001, Australia.
² Department of Civil Engineering, Monash University, Melbourne, VIC 3800, Australia.
³ Department of Construction Management and Engineering, University of Twente, Enschede, the Netherlands.
⁴ Civil and Infrastructure Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001, Australia. Electronic address: filippo.giustozzi@rmit.edu.au.

PMID: 37068664
DOI: 10.1016/j.scitotenv.2023.163488

Abstract

The study aims to conduct a comprehensive life cycle assessment (LCA) of mixed glass waste (MGW) recycling processes to quantify the environmental impacts of crushed glass as a partial substitute for virgin aggregate. Upstream washing, crushing, and sorting conducted at material recycling facilities (MRF) are the prime activities to assess whether reprocessed MGW in pavement construction is an alternate feasible solution. None of the previous studies explicitly account for the relative uncertainties and optimization of waste glass upstream processes from an environmental perspective. The study calculates environmental impacts using the LCA tool SimaPro considering design factors attributed to transportation, electricity consumption, use of chemicals, and water for reprocessing glass waste. Relative uncertainties of design variables and the national transition policy (2021-2030) from non-renewable to renewable energy sources have been validated by performing detailed Monte Carlo simulations. The correlation coefficients (r = 0.64, 0.58, and 0.49) of successive variables explain how the higher environmental gains of the glass recycling process are outweighed by diesel, energy consumption, and transportation distances. Compared to natural quarry sand, the recycled glass aggregate produced through crushing and recycling of its by-products reduces CO₂eq emissions by 16.2 % and 46.7 %, respectively. The need for a washing line at the plant, in addition to crushing, results in a higher environmental impact over natural sand by 90.1 % and emphasizes the benefits of collecting waste glass through a separate bin, hence avoiding contamination. The result indicates that the benefit of lowering emissions varies significantly when considering waste glass landfilling. Moreover, this study evaluates the potential impacts on asphalt and reinforced concrete pavements (RCP) with 5 %, 10 %, 15 %, and 20 % replacement of natural sand with recycled glass aggregate. The LCA emphasizes the limitations of energy-intensive waste glass reprocessing. The obtained results and uncertainty analysis based on primary MRF data and recycled product applications provide meaningful suggestions for a more fit-for-purpose waste management and natural resource conservation.

Keywords: Life cycle assessment (LCA); Materials recycling facility (MRF); Mixed glass waste (MGW); Monte Carlo simulations; Renewable energy; Road pavements.