Effect of different cross-section types on mechanical properties of carbon fibers-reinforced cement composites

To study the effect of shape factor, the mechanical properties of three shapes of carbon fiber, i.e., round, H-shape, and C-shape randomly oriented carbon fibers-reinforced cement composites (CFRCCs) were investigated. As a result, C-shape CFRCC showed higher tensile and flexural strength than any other shape carbon fibers-reinforced composites. It was noted that C-shape CFRCC presented stronger fiber-matrix interfacial adhesive forces, due to the mechanical anchorage into the matrix. However, the compressive strength of the CFRCC was decreased with increasing the aspect ratio and fiber volume fraction. This was probably due to the fact that the amounts of entrained air contents were increased during the mixing of each fiber. Also, both the tensile and flexural strength of the CFRCC were significantly increased by the additions of fumed silica to the composites.