Abstract:
The increasing amount of bagasse and pine needles have become a potential environmental threat to humans and wildlife, as they have serious consequences of catching fire or dumping on land. These wastes have been transformed for the first time into nano carbonaceous inerts via pyrolysis at 500 °Cand700 °C,respectively, in an inert atmosphere and utilized in the preparation of cementitious composites, to improve their strength, fracture response, and electromagnetic interference shielding. Carbonized material was characterized through x-ray diffraction analysis, scanning electronmicroscopy,energydispersivex-rayspectroscopy,Ramanspectroscopy,laser granulometry, and UV-visible spectroscopy. Samples of cement mortar with cement to the sand ratio of 1:1.5 were prepared with the addition of 0.025%, 0.05%, 0.08%, 0.20%, 0.50%, and 1.00% pyrolyzed nano-inerts by wt. of cement after the effective dispersion in water. The uniform dispersion of carbonized particles in the cementi- tious matrix was evidencedthroughthe forensic analysis. Three-point bending testof mortar prisms was conducted at 0.1mm/min strain rate in strain-controlled mode and the broken halves were tested in compression. A maximum increment of 25.36% in compressivestrengthand15.83%inflexuralstrengthwasachievedduetotheaddition of 0.20% pyrolyzed bagasse fibers and 1.00% pyrolyzed pine needles respectively. A substantialincreaseof114.15%and101.88%wasachievedinfracturetoughnesswith the addition of 0.20% pyrolyzed bagasse fibers and 1.00% pyrolyzed pine needles, respectively. The improvement in strength and ductility is associated with support- ing mechanics of crack branching, bridging, and crack contouring verified via SEM micrographs. The inertness of pyrolyzed particles in cementitious composites was verified by x-ray diffraction analysis. Furthermore, the cementitious samples were tested for electromagnetic interference shielding effectiveness (EMI-SE), and max- imum improvement of 18.02dB and 20.06dB was attained with 0.50% intrusion of pyrolytic bagasse fibers and pine needles, respectively
