Pull-out Behavior of Conventional Steel Reinforcement in Normal and High Strength Concrete

Strength incorporating properties in reinforced concrete are cardinally dependent on the bond strength developed between concrete matrix and the steel reinforcement bars. In matrix-reinforcement composite, bond strength depends on essentially two material properties, i.e., factors related to concrete matrix and the factors related to the reinforcement used. Therefore, such an investigation has been carried out in this research which determines the effectiveness of bond strength based on variations developed due to type of concrete and steel reinforcement bars. Experimental investigations were carried out to observe the effectiveness of bar diameter and embedded length on the pull-out strength of reinforced normal strength concrete (R-NSC) and reinforced high strength concrete (R-HSC). Concrete cylinders having dimensions t were casted for the pull-out tests using steel bars of different types i.e. plain, deformed and tor bars of Grade-40 and -60, of imperial bar sizes of having embedment lengths of , each. Curried reinforced normal and high strength concrete specimens were tested for pull-out test after 28-days of curing. Pull-out test results showed that for the larger dia. steel reinforcement bars i.e #5 bar, having any embedment length gives equal bond strength for varying grades i.e. Grade-40 & -60 steel bars; while, yielding was observed for #3 and #4 bars at an embedment length of . Steel bars of cause splitting of concrete cylinders both in R-NSC and R-HSC, depicting that pull-out strength decreases as the bar diameter increases. Moreover, the increase in the embedded length decreased the bond strength of concrete as well as bars having smaller dia, shoed enhanced bond strengths.