Influence of reclaimed asphalt content on the mechanical behaviour of cement-treated mixtures

For the rehabilitation of asphalt pavements the upper distressed layers are usually milled before overlaying to eliminate reflection cracking–related problems and to preserve the pavement geometry. This maintenance technique generates a large amount of reclaimed asphalt (RA) as a product of the milling operation. The recycling of RA in cement-treated base and subbase courses represents a valuable solution in terms of technical, economic and environmental benefits. However, the influence of RA on the mechanical properties of cement-treated materials (CTMs) is still not completely understood. As a consequence, CTMs using a high content of RA have not yet been widely applied. The present paper shows the findings of an experimental analysis on CTMs including 50% and 80% RA in comparison with the reference CTM consisting of 100% mineral aggregates. In particular, indirect tensile tests and unconfined compressive tests were conducted to evaluate the resistance characteristics of the CTMs. In addition, complex modulus tests and ultrasonic pulse velocity tests were performed to investigate the stiffness properties of CTMs. The investigation shows promising results as regards the use of high percentages of RA in CTMs and offers a substantial contribution for the understanding of the mechanical behaviour of CTMs.