BOND STRENGTH OF LIGHT-WEIGHT CONCRETE PULL-OUT SPECIMENS CONTAIN STEEL FIBERS
Bond between reinforcing steel bar and concrete has a critical influence on the structural behavior of reinforced concrete members. The nature of the concrete makes the bond characteristics inherently variable. The variability of the bond affects some of the more practical parameters such as the embedded length, bar diameter and cover thickness, which, in turn, considerably influence the length of the reinforcing elements used in the fabrication of the composite. In this investigation, the bond strength of normal weight, lightweight and fibrous lightweight concretes are investigated by use pull-out test results. The embedded lengths, bar diameter and cover thickness are taken as variables. The experimental work indicated that steel fibers specimens exhibited increase in bond strength about (75.45%), (126.36%) and (174.54%) when using (0.5%), (1%) and (1.5%) of total volume steel fibers respectively. Also, the specimens that are poured with (16mm) bar diameter have bond strength lower than that of small bar diameter for two types of concrete. In all concrete specimens, the specimens with large embedded length and concrete cover tend to fail by bond strength higher than that of small embedded length and concrete cover.