폐콘크리트 침목의 유류 오염 특성 분석 및 소성을 통한 재활용성 평가

The increasing prevalence of contaminated prestressed concrete (PC) sleepers requires the development of effective treatment technologies. In response to this challenge, calcination has been proposed as a promising technique to remove oil from waste PC sleeper through thermal oxidation, as well as convert calcium hydroxide (Ca(OH)₂) and calcium carbonate (CaCO₃) into calcium oxide (CaO). However, oil removal is contingent upon the depth of oil in the PC sleeper and the dimensions of the sleeper particle. Consequently, it is imperative to investigate the contamination characteristics of oil on the PC sleeper, and to optimize the calcination conditions to achieve the complete removal of oil, as well as the conversion of Ca(OH)₂ and CaCO₃ into CaO, thus facilitating the effective recycling of PC sleeper. In this study, the characteristics of oil contamination on the PC sleeper were evaluated using the Green-Ampt model, and optimal calcination conditions were proposed based on weight loss during thermal treatment. Furthermore, an assessment was conducted on the recyclability of waste PC sleepers, utilizing a measurement of the compressive strength of concrete containing calcined waste PC sleepers. Consequently, calcination removed the oil completely from the contaminated PC sleepers. Furthermore, the incorporation of calcined PC sleepers into cement, at a replacement level of 20 wt.%, demonstrated a compressive strength of 28.5 MPa after a 28 days hydration. Consequently, the calcined waste PC sleeper can be used as a replacement material for cement.