Fiber-reinforced gypsum composites with ultra high ductility: Investigation of physical and mechanical properties

The brittleness of traditional gypsum hinders its widespread utilization, despite its positive attributes as an environmentally and economically sustainable material. To tackle this challenge, Ultra High Molecular Weight Polyethylene (UHMWPE) fibers were introduced into gypsum matrix to produce a novel kind of gypsum composites with superior ductility (named Ultra High Ductility Gypsum Composites, UHDGC). Fiber content and water-gypsum ratio were investigated as experimental variables. Test results indicated that the UHDGC exhibits strong pseudo strain hardening behavior, with tensile strains capacity up to 7.4 %, which is several orders of magnitude higher than that of the original gypsum. The addition of fibers dramatically enhanced the strength and deformability of the UHDGC. With an increase in water-gypsum ratio, the compressive, tensile, and flexural strengths of the specimens decreased linearly, while toughness plateaued. Microscopic morphology analysis revealed that fibers were tightly bound to hydrated gypsum, and high fiber dosage (i.e., 2 %) led to fiber agglomeration. Furthermore, proposed prediction models for porosity and mean tensile cracking strength aligned well with test results. That can be an invaluable guide for the design and strength prediction of UHDGC.