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T. Huber, P. Huber, J. Kollegger:
"Influence of Aggregate Type on Shear Strength of RC Beams Without Shear Reinforcement";
Vortrag: fib Symposium 2016, Cape Town; 21.11.2016 - 23.11.2016; in: "Performance-Based Approaches for Concrete Structures", (2016), ISBN: 978-2-88394-120-5; S. 227 - 228.

Aggregate interlock is known to play an essential role in the shear strength of concrete structures without shear reinforcement. The contribution of this action to the shear strength depends on the kinematics of the critical diagonal crack (opening and sliding of the crack surfaces) and the roughness of the crack. In a test series carried out at TU Wien, the influences of the aggregate particle shape and aggregate fracture on the shear transfer through non-reinforced cracks were investigated. Therefore, a series of push-off tests with external restraint was performed. To reach different roughness levels, the authors used two different types of aggregate (crushed dolomite and rounded gravel) and varied the concrete compression strength. The results of these tests are compared with acknowledged approaches from literature. Furthermore, shear tests of RC beams without shear reinforcement were performed. The specimens were rectangular in cross-section and the same concrete mixes as used for the push-off tests, were applied. The kinematics of the diagonal shear crack were investigated by using three-dimensional digital image correlation. Based on these measurements linked with the results of the push-off tests, an evaluation of the impact of aggregate interlock is carried out.

Aggregate interlock, Shear strength, Push-off test, Aggregate fracture, Crack kinematics