This study aimed to investigate mechanical properties and durability of mortar containing fly ash (FA) and bottom ash (BA) as a full replacement of fine aggregate. Different combinations of BA and FA were tested for mechanical properties and durability over 180 days. The results showed that mortar containing FA and BA required extra water to achieve similar workability as the control mortar. Furthermore, 90BA:10FA and 80BA:20FA mortars had higher compressive and split tensile strengths compared to the control at all curing ages due to the contribution of the pozzolanic reaction of FA. The presence of FA reduced porosity due to the pozzolanic reaction and micro-aggregate effect. This was particularly observed at the end of the curing, showing the production of high-quality mortar. Based on the results, combining of 80%BA and 20%FA offered a sustainable alternative to naturally sourced fine aggregate that produced mortar of comparable performance.

recycling, fly ash, bottom ash, fine aggregate, mortar, sustainable