Preparation and Reinforcement Adaptability of Jute Fiber Reinforced Magnesium Phosphate Cement Based Composite Materials

To improve the brittleness characteristics of magnesium phosphate cement-based materials (MPC) and to promote its promotion and application in the field of structural reinforcement and repair, this study aimed to increase the toughness of MPC by adding jute fiber, explore the effects of different amounts of jute fiber on the working and mechanical properties of MPC, and prepare jute fiber reinforced magnesium phosphate cement-based materials (JFRMPC) to reinforce damaged beams. The improvement effect of beam performance before and after reinforcement was compared, and the strengthening and toughening mechanisms of jute fiber on MPC were explored through microscopic analysis. The experimental results show that, as the content of jute fiber (JF) increases, the fluidity and setting time of MPC decrease continuously; When the content of jute fiber is 0.8%, the compressive strength, flexural strength, and bonding strength of MPC at 28 days reach their maximum values, which are increased by 18.0%, 20.5%, and 22.6% compared to those of M0, respectively. The beam strengthened with JFRMPC can withstand greater deformation, with a deflection of 2.3 times that of the unreinforced beam at failure. The strain of the steel bar is greatly reduced, and the initial crack and failure loads of the reinforced beam are increased by 192.1% and 16.1%, respectively, compared to those of the unreinforced beam. The JF added to the MPC matrix dissipates energy through tensile fracture and debonding pull-out, slowing down stress concentration and inhibiting the free development of cracks in the matrix, enabling JFRMPC to exhibit higher strength and better toughness. The JF does not cause the hydration of MPC to generate new compounds but reduces the amount of hydration products generated.