Sustainable Inert Carbonized Intrusions For Intensification In Fracture And Electromagnetic Properties Of Cementitious Composites

Abstract

The developments in concrete engineering via successive utilization of industrial and agricultural wastes having economic, ecological and sustainability benefits; is the demand of present era. Waste scrap tire and cotton stalk poses serious environmental challenges on burning as fuel or dumping as landfill material. Emissions from burning of scrap tire are highly mutagenic and their dumping on ground leads to leaching of injurious substances to soil with an ultimate killing of healthy micro-organisms. This issue has been addressed by devising a pyrolysis setup to synthesize novel carbon particles out of the mentioned wastes with their further investigated potential in conjunction to multipurpose smart concrete. The synthesized carbonaceous particles were milled to nano-phase and then characterized by scanning electron microscopy, energy-dispersive x-ray spectroscopy, thermo-gravimetry analysis, x-ray diffraction analysis, Fourier-transform infrared spectroscopy, laser-granulometry and Raman spectroscopy in physical, mechanical and chemical modes. Both carbonized waste tire and carbonized cotton stalk based nano/micro particles were investigated as added reinforcements in cementitious mortar specimens by 0, 0.025, 0.05, 0.08, 0.2, 0.5 and 1.0 percent weight of cement to explore their impact on fracture properties, microstructure and shielding against electromagnetic waves. Fracture properties were evaluated via testing the specimens in three-point bending mode at a sensitive strain rate of 0.003mm/min. The electromagnetic-interference shielding properties of carbonized nano/micro particles reinforced cementitious composites were regulated in X-band frequency range of 8-12.5GHz using vector network analyzer (Agilent E8362B). The experiments revealed that the synthesized carbon media is easy to disperse in water and later in the cementitious matrix that contributes effectively in the refinement of microstructure leading to their added resilience in compression and flexure. The maximum increase by 48.96% in compression is attained on adding carbonaceous waste tire particles alongside 191.14% & 366.4% enhancements in rupture strain and tensile toughness respectively on 1% addition. While carbonized cotton stalk increased flexural strength by 59.7% on 1% addition to cement weight, with 292.3% & 157.6% improvements in the tensile toughness and rupture strains respectively. However maximum electromagnetic interference shielding by 24.2db is achieved on 0.5% optimum addition of carbonaceous waste tire.