Life-Cycle Assessment of Concrete Dam Construction: Comparison of Environmental Impact of Rock-Filled and Conventional Concrete

Abstract

Massive concrete dam projects will be constructed in the next 10years to respond to the increasing demand for clean energy and water resources in developing countries. Because of their ample use of cement, these projects have a significant environmental impact, including the production of carbon dioxide (CO2) emissions. Rock-filled concrete (RFC) is an innovative dam construction method that promises better environmental performance than conventional concrete (CC) in the material production stage by saving a large amount of cement. However, the environmental loads throughout the entire life cycle of a dam must be quantified. Thus, this paper aims to evaluate the environmental loads in the lifetime of a dam and reveal the environmental impact of RFC relative to CC over the entire life cycle of a concrete dam. Through reviewing the limitations of the existing life-cycle assessment (LCA) models, a hybrid LCA model is applied to achieve this goal. The results from a case study of a concrete dam project in China are presented to demonstrate the environmental benefit of RFC throughout the lifetime of a dam. The results indicate that RFC reduces greenhouse gas emissions by approximately 64% and energy consumption by approximately 55% compared with CC. With regard to each life cycle stage, RFC decreased the CO2 emissions by 72% in material production, 25% in transportation, 51% in construction, and 15.6% in operation and maintenance. The conclusion is that RFC is more environmentally responsible throughout the life cycle of a dam's, and that the environmental benefit of RFC may help to encourage decision makers to select the appropriate methods in the planning phase. (C) 2013 American Society of Civil Engineers.