Abstract:

This research involves the multiscale characterization of strain-hardening cementitious composites under tensile loading. The sensitivity of cracking behavior to fiber dispersion is studied through physical and numerical testing. Dogbone-type specimens are tested in the laboratory. At progressively larger levels of tensile strain, crack count and crack size are measured using an image analysis system. Analogous tensile tests are simulated using three-dimensional lattice models, in which each fiber is explicitly represented. Due to the diffculty in mapping large numbers of polyvinyl alcohol fibers in the material volume, fiber distributions are roughly quantified using image analyses of cross-sections taken over the gage length. In this approximate sense, the fiber distributions in the physical and numerical specimens are spatially correlated. It is shown that the nonlocal modeling of fiber bridging forces is essential for obtaining realistic patterns of crack development. Both the physical and numerical results clearly show the in uence of fiber dispersion on histograms of crack opening size.