Mechanical and water resistance properties of strain hardening fiber reinforced gypsum-based composites

Gypsum is a kind of environmentally friendly building material with broad prospects. To improve the inherent brittle nature of gypsum, a novel gypsum-based composites with strain hardening and ultra-high ductile characteristics was developed. The basic mechanical performance including tensile, compressive and flexural behavior of the developed composites were systematically studied under normal state, dry state and saturated state. Moreover, the softening coefficient was obtained to evaluate the water resistance of the gypsum-based composites. It was showed that the tensile strain capacity of the developed gypsum-based composites ranged from 4% to 7%, and the average crack width was less than 200 mu m. To further explore the strain hardening and water resistance mechanism, a series of analysis, including fiber-gypsum matrix interface bonding behavior, matrix fracture toughness and fiber bridging relationship, were made to investigate the properties of gypsumbased composites at microscopic, mesoscopic and macroscopic levels. It was demonstrated that the addition of polyethylene fibers does not improve the water resistance of the gypsum-based composites, but can significantly enhance the tensile deformation capacity.