Analysis of Life Cycle Environmental Impact of Recycled Aggregate

Abstract

This study assessed the influence of matter discharged during the production (dry/wet) of recycled aggregate on global warming potential (GWP) and acidification potential (AP), eutrophication potential (EP), ozone depletion potential (ODP), biotic resource depletion potential (ADP), photochemical ozone creation potential (POCP) using the ISO 14044 (LCA) standard. The LCIA of dry recycled aggregate was 2.94 x 10(-2) kg-CO2eq/kg, 2.93 x 10(-5) kg-SO2eq/kg, 5.44 x 10(-6) kg-PO4eq3/kg, 4.70 x 10(-)(10) kg-CFC11eg/kg, 1.25 x 10(-5) kg-C2H4eq/kg, and 1.60 x 10(-5) kg-Antimony(eq)/kg, respectively. The environmental impact of recycled aggregate (wet) was up to 16 similar to 40% higher compared with recycled aggregate (dry); the amount of energy used by impact crushers while producing wet recycled aggregate was the main cause for this result. The environmental impact of using recycled aggregate was found to be up to twice as high as that of using natural aggregate, largely due to the greater simplicity of production of natural aggregate requiring less energy. However, ADP was approximately 20 times higher in the use of natural aggregate because doing so depletes natural resources, whereas recycled aggregate is recycled from existing construction waste. Among the life cycle impacts assessment of recycled aggregate, GWP was lower than for artificial light-weight aggregate but greater than for slag aggregate.