Mechanical properties of basalt fiber reinforced magnesium phosphate cement composites

Magnesium phosphate cements (MPCs) have found a wide range of applications due to their superior properties. However, as a chemically bonded ceramic material, MPCs show highly brittle behavior. Fiber inclusion is a simple and effective way to improve their ductility and toughness. In this study, short discrete basalt fibers with different fiber contents by mixture volume (i.e. 0-1.5%) and lengths (i.e. 6 mm-30 mm) were added into MPC matrix. Properties of basalt fiber reinforced MPC composites (BFRMPCs) including workability, compressive, splitting tensile, flexural and post-peak residual strengths, and toughness were assessed. The fracture surfaces of BFRMPC samples were also investigated by using scanning electron microscopy (SEM). The results revealed that the addition of basalt fibers into MPC mixture led to a significant decrease in workability and a slight decrease in bulk density. The beneficial effect of basalt fibers on compressive strength began to weaken after 1% of fiber volume, while splitting tensile strength, flexural strength, and fracture toughness significantly increased with the increase of fiber volume. Moreover, the load-deflection behavior was highly related to the fiber content and testing age. In addition, the effect of basalt fiber lengths on the properties of MPC mixtures was insignificant. The results also suggested that basalt fiber reinforced MPCs showed better mechanical properties than glass fiber reinforced MPCs.