Potential of using residual tuff mud to produce low-carbon cement mortar

This study explores the feasibility of producing low-carbon mortar by utilizing residual tuff mud (RM) as an alternative to landfill disposal. The RM was activated through physical grinding and calcination, with grinding times of 15, 20, and 25 min and calcination temperatures of 650, 750, and 850 °C. The optimal treatment method for producing modified residual tuff mud powder (MRMP) was identified as 20 min of grinding and 750 °C calcination, based on unit strength life cycle assessment. This method resulted in a 13.4 % reduction in carbon emissions compared to 100 % OPC based mortar. The MRMP, enriched with amorphous substances, further enhanced mortar strength and resistance to chloride penetration compared with RMP based mortar. Incorporating 20 % MRMP led to a 10 % decrease in compressive strength of mortar but achieved a significant CO₂ emission reduction of 82.9 kg/m³. A 30 % replacement resulted in a CO₂ carbon emission reduction of 88.9 kg/m³ compared with the reference mortar, although it had greater impacts on other environmental categories than the 20 % replacement. Overall, this study demonstrates the capability of utilizing RM to produce low-carbon cement mortar, thereby addressing waste disposal issues while reducing CO₂ emissions.