Recycled Aggregate Concrete immunized with Bagasse Carbonized Nano/Micro Particles against Freeze-Thaw resistance

Abstract

Concrete is the most consumed material all over the world in construction industry. Recently, sustainable development and environmental awareness have become important attributes of societal growth. Waste concrete, which derives from the demolition of old concrete structures, is one of the most important construction wastes, alongside durability of concrete is main issue nowadays and different materials are added to concrete to improve especially against frost actions. Nanotechnology has revolutionized the field of materials and present a great opportunity to improve the properties of concrete via successive nano-scaled modifications. Moreover, use of nano-waste particles contributes to add into effectiveness as ecofriendly concrete. Mitigation of nano-flaws will render concrete more robust to be used in environment where it is generally avoided. In this research, CNMPs is induced into cementitious mix to make it more resilient in harsh conditions. Bagasse CNMPs were obtained from bagasse sugarcane by pyrolysis process and the characterizations were tested successfully. Five different dosages of bagasse CNMPs by mass of cement, 0.2%, 0.4%, 0.6%, 0.8% and 1% were induced in Recycled Course Aggregate concrete and its effect on frost resistance, acid attack, chloride migration, microstructure, porosity, compressive strength in comparison to control sample were studied. Test result shows that concrete was still durable after 7,14,21 and 28 freezethaw cycles. Freeze-thaw response was evaluated from scaling and internal structure damage and freeze-thaw resistance was improved. Scanning electron micrographs have verified the crack branching and crack bridging effects of induced bagasse CNMPs. Bagasse CNMPs may offer nucleation sites for hydration products (CSH gel) which make the microstructure dense and impermeable. Compressive strength before and after freezethaw exposure was determined and was enhanced with addition of CNMPs. Scaling effect of acid attack was reduced with increase in CNMPs content. Addition of CNMPs has improved chloride permeability resistance of the matrix. Reduction in porosity and making the mix impermeable due to addition of CNMPs was also verified from BET test results