Characterization of carbon fiber reinforced conductive mortars filled with recycled ferrochrome slag aggregates

Abstract

Recently, it has been known that carbon fiber, a conductive fiber, is used in different mixture designs and the development of electrically conductive cementitious materials. However, the evaluation of ferrochrome slag as a recycled aggregate in the mixture of these special concretes has still not been investigated. In this study, electrically conductive mortars were produced using 100% recycled ferrochrome slag aggregate with a particle size of less than 1 mm as filling material and using carbon fiber in 4 different ratios, 0%, 0.5%, 0.75%, and 1%. To investigate the electrical conductivity properties, the resistivity values of the samples were measured at five different times within 2–180 days. In addition, 28-day compressive strength, flexural strength, dynamic resonance, ultrasonic pulse velocity, Leeb hardness, scanning electron microscope, and X-Ray Diffraction tests were performed on all samples. The results were compared with the literature, proving that ferrochrome slag could be used as a reasonable aggregate in conductive mortars. The age effect was minimal in CF-added mixtures. With the addition of 1% CF, the resistivity values decreased approximately 40 times compared to the reference. Moreover, SEM analyses of the CF-0.75 sample showed that the CFs adhered to form a conductive network between the components in the ferrochrome-filled compact structure.