BOND AND SLIP OF PLAIN REBARS IN CONCRETE

Plain rebars are often used in precast concrete elements. The provisio n of plain rebars along either side of the precast joint will strength en its resistance and provide greater ductility. However, to fully uti lize plain rebars as reinforcement for concrete, some aspects of their behavior have to be determined, including bond and anchorage in concr ete. In this paper, the bond strength of plain rebars in concrete is s tudied. Results of pullout tests on short lengths of plain and deforme d rebars in concrete, are presented. The effects of rebar type, rebar diameter, embedment length, concrete strength, and loading rate on the bond behavior are examined. It was found that (1) the bond strength o f plain rebars was only 28.6% that of deformed rebars; (2) the slip at failure was greater for the plain rebars than for the deformed rebars ; and (3) increasing the concrete compressive strength was able to imp rove the bond properties.