Uniaxial Compression and Bending Properties of Fiber-Reinforced Magnesium Oxychloride Cement Containing Polymerized Aluminum Chloride Waste Residue

In this study, a high-toughness magnesium oxychloride cement (MOC) composite containing polymerized aluminum chloride (PAC) waste composite was developed. The effects of polyethylene (PE) fiber and PAC waste residue content on the compressive stress-strain curve, elastic modulus, compressive strength, load-deflection curve, and flexural strength of MOC composites were systematically studied through uniaxial compression and thin-plate four-point bending tests, and their flexural toughness was evaluated. Meanwhile, microscopic testing and analysis were conducted on its hydration products. The findings revealed a synergistic enhancement in the compressive properties of MOC by adding the correct amount of PAC waste residue and PE fiber. The compressive strength of the formulated composites exhibited an impressive peak of 84 MPa, with a peak strain of 0.48%. Notably, even when the strain reached 3.0%, the composite maintained residual stresses ranging from 12 to 19 MPa. Meanwhile, a uniaxial compression constitutive model for MOC composites was developed across various mixing ratios to reflect the stress-strain relationship. Moreover, the inclusion of PE fiber and PAC waste residue bolstered the bending characteristics of MOC, notably enhancing deflection and toughness in thin plates. MOC with 2% PE fiber and 20% PAC waste residue achieved an ultimate deflection of 36.75 mm, with a toughness index I max of 216.39. In addition, its flexural strength is 17.15 MPa, representing an 87.02% increase compared to the fiber-free composite. The PE-MOC composites showcased exceptional mechanical properties, effectively utilizing PAC waste residue and broadening the application space of MOC materials in the field of civil engineering.