Evaluation of the load associated cracking in flexible pavements

The overlay of a cracked pavement is subject to reflective cracking due the existing crack potential. In a cracked pavement, this cracking potential, due to traffic loads and temperature gradient, can be evaluated by means of crack activity. Traffic loads cause vertical and horizontal activity between the two edges of the cracks. These activities are caused by rocking of blocks between the cracks as well as by the shape of the deflection basin, combined with the size of the blocks. The temperature gradient causes horizontal activity between the two edges of the cracks. The main goal of this work is the evaluation of the crack activity before and after an overlay and it evolution during pavement life. This work was done monitoring 50 cracks in two trial section of an in service pavement. Models for crack activity before and after overlay were developed, based on finite elements, and applied in this case