Analysis of Life Cycle Environmental Impact of Recycled Aggregate

Won-Jun Park,Taehyoung Kim,Seungjun Roh,Rakhyun Kim

doi:10.3390/app9051021

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 × 10−2 kg-CO2eq/kg, 2.93 × 10−5 kg-SO2eq/kg, 5.44 × 10−6 kg-PO43eq/kg, 4.70 × 10−10 kg-CFC11eq/kg, 1.25 × 10−5 kg-C2H4eq/kg, and 1.60 × 10−5 kg-Antimonyeq/kg, respectively. The environmental impact of recycled aggregate (wet) was up to 16~40% 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.

Highlights

In South Korea, redevelopment and reconstruction are being actively performed due to the economic and functional service-life expiry of older constructed structures
As the volume fraction of recycled aggregate increased to 10%, 20%, and 30%, the abiotic depletion potential (ADP) decreased by 9–29% compared to the ADP of the concrete with natural aggregate only
By observing the ISO 14044 (LCA) standard, this study assessed the life cycle environmental impact of matter discharged in the production of recycled aggregate on global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone depletion potential (ODP), impact of matter discharged in the production of recycled aggregate on GWP, AP, EP, ODP, ADP, and photochemical ozone creation potential (POCP)

Summary

Introduction

In South Korea, redevelopment and reconstruction are being actively performed due to the economic and functional service-life expiry of older constructed structures. Such development inevitably generates a rapidly increasing quantity of construction waste. Waste concrete accounts for approximately 60% of the waste produced in redevelopment and reconstruction projects, and is not being effectively recycled despite attempts underway in countries such as the United States and Japan. Technology is currently under development to utilize recycled aggregate, obtained by crushing waste concrete, as a high-value-add material with applications such as aggregate for road construction and concrete. The field application of concrete using recycled aggregate is being performed with slowly increasing frequency in a variety of areas, including road construction. The construction industry has been making efforts to become an economically and environmentally sustainable industry, while continuing to face social problems such as an increase in industrial and construction waste and the measures devised to process the waste cause further environmental problems, such as pollution and resource depletion [1]

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Discussion

Conclusion