ABSTRACT
ABSTRACT This paper highlights the result of a case study on energy inputs and carbon dioxide emissions of lightweight expanded clay aggregates. These aggregates have numerous applications in various areas of civil engineering and agriculture, including lightweight construction, geotechnical backfills, pavement sections, water treatment, and horticulture. Replacement of non-renewable natural aggregates with alternative lightweight aggregates in these applications offer new opportunities and challenges. The environmental consequence of such replacement is particularly significant for geotechnical fill applications involving large volume of materials, often in direct contact with natural ground and undisturbed soil. Such significance justifies implementation of sustainable means, methods, and materials of construction. Evaluating the potential of these aggregates to enhance sustainability rating of infrastructures requires analyzing energy inputs and carbon dioxide emissions as major sustainability performance measures. These measures contribute to the production phase of any lifecycle cost analysis, where environmental footprints represent the cost. Similarly, physical and mechanical characteristics of materials, such as lightness, damping, insulation, and durability, will alter the consumption of energy and the release of greenhouse gas emissions during operation, maintenance, and decommissioning phases of the lifecycle analysis. The presented case study employs these techniques to reframe lifecycle analysis based on environmental measures and to compare the outcome with conventional cost analyses. Moreover, conclusions discuss the link between these comparative analyses and ENVISION sustainability rating measures.
