Pull-out strength of rebar in concrete mixed with bagasse ash

Pozzolan has been widely used as a supplementary cementitious material to improve concrete properties such as workability and shrinkage. Bagasse ash (BA) is an industrial waste that has pozzolanic properties like fly ash (FA), but its cost is relatively lower. Research conducted on concrete mixed with BA (CBA) were primarily on the properties of CBA, investigation on the bonding strength of steel rebars in CBA was still limited. This paper aims to investigate the effect of BA on the overall bonding strength of reinforced concrete using a pull-out testing method. Based on the range of the parameters considered in the present work, the results revealed that the bonding strength was inversely proportional to the BA content in concrete. The bonding strength of rebar in CBA was compared with that in ordinary cement concrete. It was found that the bonding strength of rebar in CBA was lower than that in concrete without BA at 28-day age. When the concrete age was more than 90 days, and BA content was not greater than 20% cement replacement, the difference in the bonding strength was insignificant. This outcome indicates that the current standard for designing the development length of rebars in CBA is still valid when the BA content is not greater than 20% of the cement. Further experiments are required to investigate any size effect.