Analysis of mortar with brake lining waste by electrical impedance spectroscopy

Abstract

Several researchers have been committed to developing multifunctional mortars, that is, beyond those usual purposes, such as laying masonry, coating, and sealing. These multifunctional mortars may be able to regenerate, store energy, and self-monitor, among other features. Some of these features involve the need to increase the electrical conductivity of the mortar. In this sense, a cement mortar was produced with gradual replacement of the sand with the brake lining waste, to evaluate the electrical impedance and phase angle in a frequency spectrum from 40 Hz to 100 kHz. The specimens had aluminum electrodes embedded in them to measure the properties in question, in the hardened state. This work is a complement to preliminary research that evaluated compressive strength and impedance only at a frequency of 60 Hz, in mortars with the same mix proportion. The results indicated that increasing the content of brake lining waste when replacing sand was able to reduce electrical resistance, both at low and high frequencies. This reduction was due to the increase in electrical conductivity caused by the composition of the brake lining waste, which gives the waste ohmic characteristics. In addition to improving electrical properties, the use of brake lining waste helps to reduce waste disposal in landfills, as well as reducing the consumption of natural aggregates.