Effect of fiber alignment on the mechanical and electrical properties of carbon fiber reinforced cementitious composites

In previous research, the utilization of carbon fibers in composite materials has garnered significant attention due to their exceptional mechanical and electrical properties.One promising method for optimizing these properties is through the control of fiber orientation during the extrusion-based 3D printing process.In this study, the orientation of long carbon fibers, specifically measuring 6 mm and 12 mm in length, was successfully controlled using extrusion-based 3D printing techniques via a syringe.The investigation focused on the effects of fiber aspect ratio, volume fraction, and orientation on the electrical properties of the carbon fiber reinforced cementitious composites (c-FRCC) under three-point bending conditions.Flexural hardening was enhanced by the controlled fiber alignment.Electrical results reveal that the electrical resistance (R) of all specimens with aligned carbon fibers is more sensitive to flexural deflection than that of specimens with random fiber orientation before localized failure.The sensitivity in the fractional change in electrical resistance, (R-R)/R, improved with increasing aspect ratio and volume fraction of carbon fibers.Understanding these relationships is essential for developing advanced materials with tailored properties for crack self-sensing.