Pull-out Response of Single Steel Fiber Embedded in PVA Fiber Reinforced Cementitious Matrix

Comparing to Strain Hardening Cementitious Composites (SHCC) with polyvinyl alcohol (PVA) fibers alone, recent test results show that the hybridization of PVA and steel fibers can improve the crack control ability and shear performance of SHCC, indicating a possible synergistic effect between the two kinds of fibers. The objective of this paper is to investigate the physical basis behind the synergy between PVA and steel fibers. As steel fibers are much larger in diameter than the PVA fibers, one can consider them to be embedded inside a PVA fiber reinforced matrix. With a specially designed testing set-up, fiber pull-out test is performed on a single steel fiber embedded inside a cementitious block with different contents of PVA fibers. In the test, the load verses displacement relationship during fiber debonding and pull-out is measured. The parameters investigated include the geometry of steel fibers, the fiber inclination angle (0°, 30° and 60°), as well as the PVA fiber volume fraction (0% as control, 1.0% and 2.0%). With the test results, it is possible to quantify the synergistic effect between PVA and steel fibers, which can be used for the optimal design of hybrid PVA/steel fiber SHCC in the future.