Impact of polyethylene fiber on the ductility and durability of magnesium phosphate cement

This study investigates the effect of polyethylene (PE) fibers on the mechanical properties and durability of magnesium phosphate cement (MPC). The role of PE fibers in physical and toughness is evaluated using compressive strength, four-point flexural testing, splitting, and direct tensile analysis. Moreover, the variation of durability with fiber admixture is analyzed by water resis-tance and electrical flux tests. The results show that the ideal dose of PE fibers effectively im-proves the ductility and durability of MPC materials. Specifically, 1.25% PE fiber is the optimum level for comprehensive performance. At this time, MPC composites can produce high peak flexural strength (15.08 MPa) and toughness (ductility index (DI) close to 7), larger tensile strain (>1.5%) and multiple fine cracks. Furthermore, the inclusion of PE fiber would improve the water resistance of MPC (PE-1.25 higher 26% than Ref.), whereas it could decrease the resistance to chloride ion penetration (but charge still <400C), which is still much lower than other concretes (at least 60% lower than HPC). Besides, scanning electron microscopy (SEM) measurements show that the fiber agglomeration at 1.5% dosing, resulting in a vulnerable "weak link" within the material. This research displays the potential of PE fibers in the exploitation of high-performance MPC-based marine engineering repair materials.