Investigation of the shear performance of multi-key block bonding surfaces without connecting reinforcement for...

The surface roughness of precast elements significantly impacts the shear performance of the bonding surface (BS). To enhance roughness while minimizing environmental impact, this study introduces a frustum multikey block rough surface created via a mold. To assess the shear performance of this key block BS, push-off tests were conducted on 48 specimens. The study focused on key factors such as the types of BS, key block sizes, defect rates, confining stress levels, and concrete strength classes. The results revealed that the key block BS exhibited the highest shear capacity (V_u) among all BS types. V_u increased with increasing key block size and confining stress and concrete strength but decreased as the defect rate increased. Additionally, finite element simulations and prediction formulas for V_u were developed, and the results closely aligned with the test data.