title: Recyclability of bottom ash mixed with dredged soils according to the transportation distance and mixing ratio through the estimation of CO2 emissions.
abstract: Bottom ash and dredged soils can be used as construction materials because they are similar in physical characteristics to natural aggregates. However, whenever such byproducts as bottom ash and dredged soils are used, the energy efficiency of recycling is offset to a certain degree by emissions from transportation. The objective of this study is to analyze the environmental efficiency of recycling bottom ash and dredged soils through the estimation of CO2 emissions, considering both transportation distance and the mixing ratio. Agricultural reservoirs were selected as the final destinations of these recycled materials. This analysis demonstrated that using 100% bottom ash emits less CO2 than using natural aggregates when the ash is transported less than 35.15 km. This breakeven distance increases exponentially with the mass fraction of admixed dredged soil. However, admixture with natural soils does not affect the breakeven distance. Using the breakeven distances, the effective area with which it is efficient to recycle bottom ash was delineated. When dredged soil is admixed to a mass fraction of 70%, the effective area covers most of South Korea. In addition, 100% bottom ash was efficient in 1622 reservoirs (9.45%) in terms of CO2 emissions, and the mixture with 30% bottom ash and 70% dredged soils is efficient in 98.83% of all of the reservoirs in Korea. Bottom ash is most useful for reducing CO2 emissions when it is mixed with dredged soils, which are a byproduct of construction found on-site. This result is meaningful because bottom ash and dredged soils are complementary in their physical characteristics, and they need to be mixed before use as construction materials. The recycling of bottom ash becomes even more attractive with anticipated improvements in fuel efficiency.
authors: Research Institute for Agriculture & Life Sciences, Seoul National University, Seoul, South Korea.
authors: Sookack
authors: S
authors: Noh
authors: Research Institute for Agriculture & Life Sciences, Seoul National University, Seoul, South Korea; Department of Rural Systems Engineering, Seoul National University, Seoul, South Korea. Electronic address: syh86@snu.ac.kr.
authors: Younghwan
authors: Y
authors: Son
authors: Department of Rural Systems Engineering, Seoul National University, Seoul, South Korea.
authors: Taegang
authors: T
authors: Yoon
authors: Research Institute for Agriculture & Life Sciences, Seoul National University, Seoul, South Korea.
authors: Taeho
authors: T
authors: Bong
mesh_terms: D000383:Agriculture; D002245:Carbon Dioxide / Q000032:analysis*; D058572:Carbon Footprint; D060729:Coal Ash / Q000737:chemistry; D003247:Conservation of Natural Resources / Q000379:methods*; D003252:Construction Materials; D019015:Geologic Sediments / Q000737:chemistry; D008962:Models, Theoretical; D059027:Recycling / Q000379:methods*; D056910:Republic of Korea; D014186:Transportation
chemical_list: D060729:Coal Ash; D002245:Carbon Dioxide
keywords: Bottom ash; CO(2) emissions; Dredged soil; Recycled materials; Transportation