Enhanced durability of recycled aggregate concrete with sugarcane bagasse biochar

Sustainability necessitates material recycling and emphasizes the urge to save the environment. Recycling aggregates in concrete development, though, ensures conservation of volumetric-intensive aggregates but has been found to compromise the required strength and durability of concrete structures. Nano-micro scaled biochar particles synthesized from sugarcane bagasse through pyrolysis have been investigated in this paper to enforce the weak links affecting strength and durability characteristics of recycled aggregate concrete (RAC). The synthesized biochar named carbonaceous nano-micro particles (CNMPs) has been added in five different dosages by mass of cement, 0.2%, 0.4%, 0.6%, 0.8% and 1%. It’s effect on frost resistance (covering scaling and internal structure damage), compressive strength, porosity, acid attack, chlorides migration, and microstructure was analyzed. CNMPs improved the strength and durability of RAC at each investigated age due to refined pore-structure, increased hydration and the crack arresting features. Scanning electron micrographs confirmed the crack branching and crack bridging effects of induced CNMPs, whereas the nitrogen adsorption evidenced the associated refinement of pores. CNMPs enhanced the compressive strength and significantly reduced scaling, mass loss, and chlorides permeability of RAC mixes under aggressive environment. The work finally revealed a promising carbon-based additive out of waste which can effectively contribute to performance enhancement of RAC alongside reducing its negative environmental burden.