Effect of different parameters on coefficient of friction between rigid pavement and subbase layer

The coefficient of friction is a quantity indicates the ratio of frictional force between objects. As pavement experiences thermal changes, it may slide against supporting subbase resistance. This resistance must be determined in order for pavement to perform as anticipated. Cracking of concrete does not occur if the pavement is jointed. In the joint plain concrete pavements, A separator layer is installed between the subbase and the plate to smooth the interface. A smooth surface shows less resistance to the concrete's displacement caused by temperature difference. Two stages of the push-off test were conducted for subbase conditions (smooth and rough). Friction properties among the concrete and subbase were investigated based on the friction test results. The results show the parameters impacting the maximum coefficient of friction and displacement (interface condition, movement rate, thickness) respectively for friction and (movement rate, interface condition, thickness) for displacement. In conclusion, the frictional force rises significantly until the applied force reaches the stable condition. This force is affected by interface condition, which has the most significant impact, followed by movement rate and thickness. Changing conditions from smoother to rougher interface leads to raising maximum coefficient of friction regardless of changing slab thickness or movement rate.