이산화탄소 미세기포를 이용한 도시 생활 쓰레기 소각 비산재 탄산화 처리 및 시멘트계 혼화재로서의 활용

초록

This study investigates the modification method of municipal solid waste incineration fly ash (MSWIFA) using CO2 microbubble carbonated water and evaluates its physical and chemical properties when incorporated into cement mortar. Three types of MSWIFA were prepared: untreated (AFA), water-washed (WFA), and washed with CO2 microbubble carbonated water (CFA). Each type was used to replace ordinary Portland cement at substitution levels of 10 wt% and 20 wt%. Their chemical characteristics, flowability, expansion behavior, and compressive strength were analyzed. The results showed that both water washing and CO2 microbubble washing effectively removed alkali metals and chlorides from AFA. Notably, an additional 1.8 % of CaCO3 was formed in CFA due to carbonation from dissolved CO2 within the microbubbles. The presence of Al0 in AFA caused hydrogen gas release, leading to expansion and a decrease in compressive strength. Mortars containing WFA demonstrated improved performance compared to those with AFA due to the washing effect. Furthermore, the additional CaCO3 formed during the CFA preparation contributed to enhanced mechanical properties. In particular, CFA_10 achieved approximately 90 % of the compressive strength of the control mortar at all curing ages, indicating the most favorable overall performance.

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