Life cycle assessment of soil stabilization using cement and waste additives

Document Type

Article

Publication Date

11-3-2023

Department

Department of Mechanical Engineering-Engineering Mechanics

Abstract

Environmental measures show that the effect of global temperature rise goes beyond the natural cycle of the Earth's environmental system, which affects the social, economical, and health conditions of humanity. In this respect, initially, the UN's sustainable development goals were adopted where, more recently, a UN net-zero coalition was formed to cut greenhouse gas emissions to as close to zero as possible by 2050 to resist foreseen catastrophic outcomes. As a result of these overwhelming goals and regulations, many nations are setting policies to achieve those targets. Nevertheless, such targets, to the best of our knowledge, have not penetrated well into construction applications. In this study, in addition to the mechanical responses of three different waste additives (bottom ash, marble dust and tire rubber powder to replace cement to stabilize problematic soils, a life-cycle assessment was performed to evaluate environmental impacts. Furthermore, a novel impact-performance approach has been introduced to satisfy safety, performance, and sustainability criteria. In this respect, unconfined compressive strength (UCS), initial stiffness (G0), accumulated loss of mass (ALM) due to wet-dry cycles, and life-cycle analysis (LCA) were performed on artificially cemented (7%, 10%, and 13%) clay specimens, compacted at 1600 and 1800 kg/m3 and cured for 28 days. Further, bottom ash (BA) (10% and 20%), marble dust (MD) (20% and 40%), and tire rubber powder (TRP) (2.5%, 5%, 10%, and 20%) were used to replace the cement, which is known for its great environmental impact. It is reported in this study that 2.5% TRP replacement of cement at low density seems to be the optimum dosage and additive, among others, to provide the best performance (UCS, G0, and ALM). Furthermore, the increase in cement content and density results in a positive contribution to performance indicators and a negative contribution to environmental impact. However, when impact-performance is considered, the opposite was observed, i.e., the rise in cement content, additive content, and density results in favourable contributions.

Publication Title

Construction and Building Materials

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