Vehicular soot for improvement of chemical stability of cement composites towards acid rain and sewage like atmospheres

This study explores the use of vehicular soot, an otherwise waste product, for protecting cement based composites against corrosion and degradation due to acid rain and sewage like atmospheres. Cement mortar cubes (volume 70.7 x 70.7 x 70.7 mm(3)) were coated with colloidal vehicular soot dispersed in ethanol medium using a simple drop casting technique. The coated cement mortar specimens were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The protective role of soot coating against acid rain and sewage atmospheres were assessed by crack propagation and water absorption tests. Specimens, previously subjected to stress until minor cracks become visible, were employed to study crack-propagation as a function of time. The reasoning for the observed variation between the coated and the reference sample are discussed. The mechanism of enhanced acid resistance property of coated mortars is explained based on the hydrophobic and water absorptive behavior of soot. Present study presents a novel and economical technique for corrosion protection of cement based composites. (C) 2020 Elsevier Ltd. All rights reserved.