LAUSR

Abstract Rising amounts of cotton-crop residue and waste scrap tires are potential environmental challenges and poses serious health hazards on discarding as landfill materials or burning as fuel. This waste has been successively converted into nano-carbonaceous reinforcements with their explored potential in the fabrication of multipurpose concrete. Initially, bio-char was prepared via pyrolysis of cotton stalk and waste tire at 500 °C in nitrogen atmosphere followed by its milling into nano/micro phase. The synthesized nano particles were added in cementitious mortar specimens in 0, 0.025, 0.05, 0.08, 0.2, 0.5 and 1.0% by weight of cement to explore the effect of their added content on electromagnetic shielding and fracture toughness of cementitious composites. It was resolved experimentally that effortlessly uniform dispersion of nano/micro inerts in mixing water and host matrix were accomplished that effectively produced interfacial polarization which contributed in significant improvement of electromagnetic-interference shielding by 22.9 db and 24.2 db on 0.5% optimum addition of carbonized cotton stalk and carbonized waste tire respectively. Besides, packing effects of nano/micro inerts intrusion in cementitious composites reduced the porosity. Moreover, crack pinning and deflection are the phenomenon which resulted in more ductile rupture of specimens with 59.7% and 48.8% enhancement in fracture toughness on 1.0% addition of carbonized cotton stalk and carbonized waste tire respectively.