Partial Use of Pseudo-Ductile Cementitious Composites in Concrete Components to Resist Concentrated Stress

Abstract

The high pseudo-ductility of Engineered Cementitious Composites (ECC) makes it a particularly effective material to resist the propagation of cracks. In applications where failure is due to cracking initiated by localized stresses, the application of ECC around the stress concentrated region should result in significant improvement in the ultimate failure load. In this investigation, we will study the use of ECC in (i) the anchorage zone of post-tensioned concrete members, and (ii) the region around embedded anchor bolts in concrete blocks. For the first application, the replacement of concrete with ECC at the anchorage zone is found to be very effective in increasing the load capacity under concentrated compression. Based on our test results, ECC can actually replace all or part of the conventional steel stirrups in resisting splitting failure at the anchorage zone. For embedded anchor bolts, the placement of a small ECC disc above the steel bolt can effectively delay the propagation of cone-shape failure and increase the pull-out force. Through the present experimental program, we have illustrated the advantage of strategically applying ECC in critical region of structural components, to improve performance without significant increasing the material cost.