Mechanical properties of sustainable concrete made with partially substitution of volcanic ash: a review (part I)

This review aims to collect the positive and negative influence of volcanic ash (VA) on concrete properties. The review discussed a general background of VA, classification, preparation, chemical aspects and its impact on concrete properties. Furthermore, the performance at elevated temperatures and environmental benefits associated with the utilization of VA are also discussed. The finding reveals that the concrete flow properties and strength properties improved with VA due to micro filling and pozzolanic action. The optimum percentage of VA varies from 5 to 10% depending on the source of VA, mix design, and aggregates. Also, VA-based concrete performance is comparable with conventional concrete at elevated temperatures. Furthermore, the environmental assessment shows that the utilization of VA decreased CO₂ emissions. The assessment concluded that conflict exists among different researchers as some researchers observed a positive impact while some researchers observed a negative impact on concrete performance. Therefore, the study recommends further research to identify the exact parameter that causes variation.