The mixed-mode fracture behavior of a mortar reinforced with vinylon fibers is investigated in this paper, in order to ascertain to what extent this material is suitable to be used in seismic-isolation devices. Since most of the studies on fracture…
The mixed-mode fracture behavior of a mortar reinforced with vinylon fibers is investigated in this paper, in order to ascertain to what extent this material is suitable to be used in seismic-isolation devices. Since most of the studies on fracture mechanics of cement-based materials have regarded so far Mode I frac- ture, standard tests are limited to this type of behavior. However, an increasing number of researchers are in- vestigating whether Mode II (shear fracture) exists and how its parameters can be measured. Starting from the assumption that Mode II exists (even if it is generally combined with Mode I), this study aims to investigate the fracture properties of the above-mentioned fiber-reinforced mortar, in order to assess its energy- absorption capability, in view of possible application to seismic devices. In this project, 4-point shear tests on notched prisms were carried out, and both the crack-mouth opening displacement (CMOD) and the crack slid- ing deformation (CSD) were measured by means of 2-axis LVDTs. Since the specimens were longitudinally confined by tightening two external steel bars, the favorable effect that the confinement has on mortar tough- ness was investigated as well. The evolution of the load versus CMOD and CSD was also monitored, to have information on mixed-mode fracture, as a step towards the still elusive formulation of appropriate con- stitutive laws for cementitious materials.