Mechanical and electromagnetic performance of cement based composites containing different replacement levels of ground granulated blast furnace slag, fly ash, silica fume and rice husk ash

Abstract

In this study, cement additives were replaced with cement in mortar mixtures by mass. Mortar specimens were prepared with different additives and dosages which were mechanically and electromagnetically tested. According to the compressive strength test results, mortars containing ground granulated blast furnace slag had weak early age strength and strong later age compressive strengths values, mortars containing fly ash had lower compressive strength value with increasing amount of additives in the mortar mixture for both 7 and 28-day samples, mortars containing silica fume had the maximum strength values at 20% replacement level and lastly the mortars including more than 10% rice husk ash showed weaker strength behaviors with increasing amount of rice husk ash. Besides, electromagnetic responses of the mortar samples were investigated in the frequency range of 3-18 GHz. The reflection and transmission values were measured and the absorption characteristics were calculated. According to the electromagnetic test results, it is revealed that the mortars including ground granulated blast furnace slag can be utilized in the applications of high stealth technology and electromagnetic shields in a wide frequency range of communication field. An increase in the ratio of fly ash in the mortars reduces the transmission of the electromagnetic wave. Mortars including silica fume had very low values of reflection and transmission. Hence, it is expected that the absorption values must be high due to dependency of absorption to reflection and transmission, and it can be said that mortar with rice husk ash exhibits a strong absorber behavior.