The Effect of Stress Absorbing Membrane Interlayer (SAMI) On Fracture and Creep Resistance of Asphalt Overlay

Overlaying the old pavement with new surfacing material is one of the commonly used methods for rehabilitating deteriorated pavements. The existing cracks in the old pavement propagate through the newly laid overlay and reach the free surface in due course of time. This phenomenon is referred to as reflection cracking. In general, using of stress absorbing membrane interlayer (SAMI) is one of the methods to control reflective ceacking. The main aim of this study is the evaluation of performance of SAMI in high stress level. The SAMIs in this study made by porous asphalt and Stone Mastic Asphalt (SMA) and paved between the old asphalt pavement and new surfacing layer. To do so, first test specimens made up of 2 and 3 layers which respectively were without and with SAMI. Afterwards to investigate the performance of SAMIs, dynamic creep test and specific fracture test by new geometry carried out. The fracture test able to simulate/model reflective growth in mixed modes I/III of fracture mechanism. The findings of study indicated that using this type of SAMIs reduce the fatigue life and cannot able to retard reflective cracking. Also, using SAMIs result in deformation increase.