ScholarWorks@중앙대학교

초록

This study explores the potential of utilizing coal bottom ash (CBA) as a substitute for sand by removing its amorphous phases through NaOH treatment. The depletion of natural sand resources and the environmental impact of CBA disposal are significant concerns. However, the high content of amorphous phases in CBA leads to increased water demand and reduced compressive strength in mortar, thereby limiting its feasible sand replacement ratio up to 20 %. A series of experiments demonstrated that treating CBA with a NaOH solution effectively removes these amorphous phases, enhancing its crushing resistance by 20 %. As a result, mortar incorporating NaOH-treated CBA at 75 °C for 24 h exhibited a 46 % increase in compressive strength at 3 days and a 50 % increase at 7 days, compared to mortar containing untreated CBA. Notably, the NaOH-treated CBA also achieved 10 % higher compressive strengths at 28 days than natural sand. These findings suggest that NaOH treatment is a promising approach for repurposing CBA as a fine aggregate in mortar. © 2025 Elsevier Ltd

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