The paper presents the first part of a study on bond. It reports the research conducted on bond strength of short length specimens (Local Bond Strength) in normal strength and high strength concrete (HSC). For normal strength concrete, using the test results available in the literature, Tepfers' partly cracked thick cylinder theory is modified to account for the variation of the bursting angle and the tensile plastic deformation of the concrete. The study of local bond in HSC included tests of forty five short length specimens using two types of bars with different rib face angles. For different ranges of concrete strength, a relationship for bond strength normalised with respect to the tensile strength of concrete is obtained. The normalised bond strength increased with the compressive strength of concrete. The silica fume in the HSC mix decreased the bond strength. The bond strength of the bars with rib face angles between 23 and 27 degrees is smaller than that of bars with rib face angles between 40 to 47 degrees.

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