Coal bottom ash characterization aiming the incorporation in cellular concrete

Abstract

Ahead of the incorporation of residues in concrete composition, there is a decline in the environmental impact of buildings. One of the goals of today’s development is the employment of low-impact energy sources, such as thermoelectric. Thermoelectric industries display a high rate of residues, among which is pointed out coal bottom ash (CBA) (15% total residues), which have density superior to fly ash and accumulates in silos. Considering this scenario, this paper assessed the incorporation feasibility of CBA in the composition of cellular concrete, replacing silica fume. This study comprehended CBA characterization and application. For such, it was performed a scanning electron microscope (SEM) associated with Energy dispersive spectroscopy (EDS) analysis, laser granulometry, X-ray diffraction (XRD), X-ray efflorescence and density. Following the incorporation of the residues in cellular concrete in place of silica fume, it was performed compression strength analysis and SEM anew, evaluating the impact of CBA’s insertion in concrete’s microstructure. The XRD results are complementary to the other analyses. With SEM technique, it was observed the predominance of spherical-shape particles. The compressive strength of CBA concretes was superior to the reference concrete from 0,13 to 0,74MPa.