Utilization of thermal plasma decomposed municipal solid waste bottom ash as partial cement and fine aggregates replacements on cement mortar properties

Abstract

This study examines the synergistic effects of bottom ash in mortar production. The bottom ash used in the study was derived from thermal plasma decomposition of municipal solid waste. In the first part of the study, mortars were prepared with varying levels of ash as replacements: 5 %, 10 %, and 15 % for cement replacement and 15 % for sand replacement. The results reveal that using ash as a cement replacement reduces workability by 6.53–13.40 %, compressive strength by 10.93–24.15 %, flexural strength by 12.23–35.55 %, and increases water absorption by 0.79–26.11 % compared to the control. However, ash content of 5–10 % reduces porosity by 2.73–4.32 %. In the second part, washed and unwashed ash was used as a sand substitute at levels of 10–30 % in mortar. Incorporating 10–20 % ash improves compressive strength by up to 14 % and exhibits a slight enhancement in flexural strength, lower porosity, and lower water absorption. Interestingly, only unwashed ash enhances mechanical strengths without affecting porosity and water absorption. These findings demonstrate the potential of bottom ash in improving mortar properties. However, further research and optimization are recommended to maximize the environmental benefits and overall performance of mortar production.