Doctoral thesis focuses on behavior of the interface between two concrete layers cast at different times and without shear reinforcement. By means of both experimental and numerical analysis, some of the factors affecting interface strength have been assessed. Namely, surface roughness and suitability of different roughness parameters used for its characterization, effects of overlay mechanical properties and collateral effects of surface preparation methods. Also, different tests to assess interface strength have been investigated in detail and mutually compared.
The most suitable roughness parameters have been chosen, based on its overall stability. Correlation between mean texture depth and other parameters have been defined. Results of the experimental program intended to further investigate abovementioned effects on interface strength, led to proposition of extended semi quantitative design approach and introduction of coefficient of surface preparation. Based on the extensive experimental program, correlation between different test setups, including its main advantages and disadvantages, has been presented, together with roughness characterization and failure envelope of the dimpled interface.