Complex modulus change within the linear viscoelastic region of the mineral-cement mixture with foamed bitumen

摘要

Deep cold recycling with foamed bitumen (FB-RCM) is currently one of the most widely used road rehabilitation methods. As the percentage of reclaimed asphalt pavement (RAP) in the base mixture may vary with the thickness of recycled bituminous layers, it is vital that the rheological characteristics of the recycled base are evaluated within the linear viscoelastic (LVE) region of response. Calculating complex modulus as a function of loading time and temperature enables the acurate determination of stress and strain distributions for individual conditions. These parameters are of most relevance in the case of a base layer, especially of a recycled base layer, as they provide information needed to determine the limit state in the subgrade and the probability of creep occurring in the recycled base. An increase in the viscous part (E-2) of the complex modulus (P) is an indication of a possible creep growth. A higher RAP content in the recycled base layer is likely to increase creep in this layer, thereby reducing the load bearing capacity of the entire pavement layer system.