Experimental methods for the analysis of the tensile behavior of concrete joints

Adhesion plays an important role in the evaluation of hydraulic structures with unreinforced concrete joints. The experimental determination of joint tensile strength as a quantifiable parameter is not standardized, resulting in a variety of test setups found in literature. The present paper highlights advantages and disadvantages of three of the most common tension tests for plain concrete and concrete joints through both theoretical and laboratory experimental analysis on specimens with artificial joints. Splitting tension tests were found to be inexpensive but tend to overestimate the adhesive strength of weak joints. Direct tension tests require an elaborate test setup but may yield information on the tension softening behavior. Pull-off tests stand out for their ability to yield in-situ results but deliver inconclusive results.