EXPERIMENTAL EVALUATION OF THE DIRECT TENSION - PULLOUT BOND TEST

SUMMARY This paper presents results of an experimental investigation of the performance of an alternative bond test known as DTP-BT (Direct Tension Pullout Bond test) designed to quantify the lower bound bond properties of steel and GFRP bars embedded in normal strength concrete. Objective of an alternative test setup was to simulate the stress field that develops in the concrete cover surrounding the reinforcement in the tension zone of flexural elements. Parameters of the experimental investigation were, the axial stiffness of the bar and the amount of external confinement. Conventional pullout and beam-splice tests were also done for comparison. It was demonstrated that the most adverse conditions for bond, which occur when the cover concrete is under a direct tension stress field, result in bond properties that differ substantially from those obtained by most established conventional bond tests.