Physical and mechanical properties of sustainable bamboo coarse aggregate concrete

This study explored the potential of using biomass bamboo aggregates (BAs) developed from bamboo to replace natural aggregates (NAs) in concrete. The use of BAs not only solves the problems of environmental damage and energy depletion caused by NA mining but also improves the toughness of concrete. To address the weak adhesion between bamboo and cement, a method for modifying the surface of the BA with an epoxy mortar coating was proposed. Experimental works have examined the workability, physical, and mechanical properties of bamboo aggregate concrete (BAC) at various BA replacement rates (r=0%similar to 45%) and modification methods (unmodified, epoxy mortar-modified). The results indicated that BAC with r >= 35% exhibited good workability. As r increased, the water absorption rate increased, and the density decreased. Compared with normal aggregate concrete (NAC), BAC exhibited extended cracking and failure processes, suggesting that it has a postcracking deformation capacity. For BAC, the increase in the early strength growth was slower, but the increase in the strength later was faster, especially with higher BA contents. Despite larger r had negative effects on the mechanical properties, BAC with r >= 35% still met the strength criteria for non-load-bearing and secondary structures. Additionally, BAC exhibited a more pronounced size effect than NAC, but this effect diminished as the BA content reached 25%. Finally, equations for the 28-day strength and size effects of BAC specimens with varying r values were proposed.