Evaluation of sustainability performances of recycled aggregate concrete through life cycle perspectives

Abstract

Recycled aggregate concrete (RAC) is expected to be a sustainable solution that partially replaces virgin aggregate concrete (VAC) in the construction industry, while alleviating the problems including natural resource depletion, waste generation and global warming. Recent studies have shown adequate evidence that RAC can be used practical for structural purposes, but its broad sustainability potential, particularly in environmental performance, has not been explored sufficiently. Additionally, owing to the lack of a comparative framework, comparing the environmental impacts of different concrete products in the same system to support decision-making is challenging.

To close the research gap, this research employed a well-recognized environmental management technique, the life cycle assessment (LCA), to evaluate the environmental performance and sustainability potential of concrete and offer a guideline for LCA comparisons for different products. This was accomplished by: (1) investigating the LCA mechanism and its implementations to RAC, (2) proposing a universal LCA framework for both VAC and RAC, (3) evaluating the environmental impacts of concrete from multiple scientific studies, and exploring the influencing factors in LCA results, and (4) architecting a prediction model for predicting the environmental impacts of concrete with the assistance of a multilayer perceptron (MLP).

This thesis is the first to develop a universal LCA framework for concrete that comprehensively considers different mix design parameters, and to explicitly discuss the influences of LCA uncertainties from these selections. It offers a guideline to compare the environmental impacts of different concretes under the same system, and a proposed concrete can be compared with sustainable concretes in established databases. Moreover, the prediction model built in this research is also the first to forecast the environmental impacts of concrete without requiring LCA software, knowledge, and training. This model, as well as the recommendations provided from research outcomes, will contribute to the implementation of LCA to concrete, the reduction of the environmental footprint of concrete, and the promotion of RAC utilization.

Date of Thesis submission	2023
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Vivian Tam (Supervisor), Khoa Le (Supervisor), Jian Li Hao (Supervisor) & Jun Wang (Supervisor)