On guidelines for mix proportioning of concrete incorporating coal bottom ash as fine aggregate

This study presents simple and practical guidelines for mix proportioning of concrete incorporating coal bottom ash as a fine aggregate. The research involved preparing mortars using raw and size-controlled bottom ash, varying w/c, and different bottom ash contents. The properties for performance-based structural design properties, including compressive strength, carbonation depth, and chloride penetration depth, were measured. In addition, the compressive strength results of bottom ash concrete reported in the literature were analyzed. Furthermore, the standard specifications of mix proportioning for structural concrete from various nations were reviewed. The results indicate that when the specific gravity of bottom ash exceeded 2.0, and its content in the concrete was below 200 kg/m³, there were no concerns regarding the strength. Moreover, incorporating pretreated bottom ash aggregate in mixtures within the w/c range of 0.35–0.50 did not significantly impact the depth of chloride penetration or carbonation.