Experimental work on mechanical, electromagnetic and microwave shielding effectiveness properties of mortar containing electric arc furnace slag

Abstract

It is well known that one of the widely used structural materials is ordinary cement mortar. Whereas the mechanical properties are sufficient as structural materials, its shielding effectiveness and prevention properties of microwave signal is insufficient due to the lack of electromagnetically conductive components. Electric Arc Furnace Slag (EAFS) is a by-product which is produced after the melting and the primary acid refining of liquid steel. It has potential to improve both mechanical and electrical properties of cement. In this study, ordinary cement mortar specimens with Electric Arc Furnace Slag are investigated. The EAFS used in this study takes part in the mortar specimens as aggregate. Electrical properties are measured by a vector network analyzer in the frequency range of 3-18 GHz. Both the reflection and transmission of the proposed specimens exposed to EM wave are evaluated by free space measurement techniques at the same frequency range. The compressive strength, flexural tensile strength and shielding effectiveness of mortars are also tested, respectively. The real part of permittivity increases with the increased EAFS content of the mortars up to dielectric constant of 40. Nearly constant and frequency independent characteristics of specimens have potential applications. Furthermore, the effective dielectric constant of permeability of the mortars is explicitly improved in the related frequency ranges with the addition of the EAF slags. The transmission prevention of the EAF slag mortars tend to increase significantly with the increasing ratio of EAF slag content. The minimum transmission is around -70 dB and the transmission below -10 dB for 40% EAF aggregate ratio in mortar which has the best mechanical properties in the entire frequency range and averagely and it is -10 dB lower than that of the cement without EAF aggregates. The shielding effectiveness is in excellent level for 80% and 100% EAFS aggregate levels and that of 40% aggregate ratio is still in a good level with a value varying between 15 dB and 20 dB. Besides, the mortars with 40% EAF slag content exhibit approximately 7 MPa higher compressive strength value and 0.9 MPa higher flexural tensile strength. (C) 2018 Elsevier Ltd. All rights reserved.