Bond of reinforcement with normal-weight fiber reinforced concrete

Abstract

In reinforced concrete members, upon loading, tensile stresses from reinforcement to concrete transfer via bond. Proper bond between the two material guarantees safety of such members. This paper presents test results performed on Pull-out specimens for evaluation and comparison of bond strength behavior of Normal-weight Fiber Reinforced Concrete (NWFC). Test parameters included reinforcement size and fiber content. Three different reinforcement sizes (10, 16 and 20 mm) and four concrete mixes having fiber contents of 0, 20, 40 and 60 kg/m3 were used for current experimental work. In total, 36 Pull-out specimens were tested; although the size of specimens varied with reinforcement size, concrete cover to bar diameter ratio (c/db) remained constant. From the selected range of fiber content used in current experimental work, dosage of 40 kg/m3 was found to have positive effect on most of the concrete properties. Test results indicate decrease in ultimate bond strength with increasing bar size. The effect of fibers was not observed in enhancing the pre-crack performance of the test specimens, whereas the ultimate bond strength and post peak bond strength performance increased significantly. The ultimate bond strength is found to be strongly affected by the compressive strength rather than fiber volume.