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Assessment of Leaching Characteristics of Alkaline and Heavy Metal Ions from Recycled Concrete Aggregate

신택수 1 Hong Sangpyo 2 KIM KWANG YUL 3

1동림건설기술(주)
2청주대학교
3충북대학교

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ABSTRACT

Generation rate of construction wastes in Korea has occupied preponderantly in recent years. Although Korean government has made efforts to increase recycling rate, classification based on chemical properties of construction wastes has not been well defined. The objective of this study is to understand chemical properties of recycled concrete aggregate (RCA). RCA was tested for its leaching characteristics. Leaching tests were conducted the following procedures in Korean standard leaching test (KLT) and toxicity characteristics leaching procedure (TCLP), respectively. The RCA samples were characterized using X-ray fluorescence (XRF). Alkalinity of the leachate was determined using a pH meter titration method. The XRF analysis result shows that the calcium oxide (CaO) content in the RCA sample is 25.3~50.4 %. When the RCA sample was mixed with water in a batch reactor, pH in the solution was rapidly increased, and 70% of the total pH change was found in 1 hour. The TCLP showed slightly higher efficiency for leaching heavy metals than the KLT. The leaching efficiency was also higher as the particle size of RCA sample was smaller. The leaching test results suggest that RCA can be generally classified as non-hazardous waste.

Citation status

* References for papers published after 2022 are currently being built.