Effect of fiber properties and matrix composition on the tensile behavior of strain-hardening cement-based composites (SHCCs) subject to impact loading

The article at hand describes the behavior of high-strength and normal-strength strain-hardening cement-based composites (SHCCs) made of fine-grained matrix and high-density polyethylene fibers under quasi-static and impact tensile loading. The dynamic tension testing of unnotched and notched cylinders was performed using the Hopkinson bar at strain rates of around 150 s(-1). The responses of the materials under dynamic and quasi static tensile loading were compared to the corresponding results for normal-strength SHCC made of polyvinyl-alcohol fibers as obtained in previous investigations. To explain the pronounced differences in rate effects on the material performance of various SHCC compositions, cracking pattern and fracture surface conditions were studied. Additionally, strain rate dependent changes in the mechanical behavior of individual fibers and in the fiber-matrix interfacial properties were deduced from single-fiber tension tests and fiber pullout tests, respectively. Altogether, the results obtained provide clear indications as to the decisive parameters for a purposeful material design of impact resistant types of SHCC for use in structural elements or protective overlays.