Compactability and thermal sensitivity of cement–bitumen-treated materials

Full depth reclamation is one of the most used rehabilitation methods for subbase courses in high-traffic roads. The use of both cement and bituminous binder as binding agents for reclaimed pavement materials can lead to mixtures having high bearing capacity and resistance to permanent deformation, avoiding premature cracking due to shrinkage. This paper focuses on two main topics: compactability and thermal sensitivity of cement- bitumen treated materials (CBTM). Liquid dosage in CBTM is a key parameter in order to obtain an effective compaction. The volumetric characteristics and the optimum liquid content of CBTM were studied by means of two compaction methods: Proctor and shear gyratory compactor. The temperature susceptibility of CBTM can be a valuable factor in both design and construction quality control. The influence of temperature on the stiffness modulus of CBTM was investigated using two testing methods: indirect tensile stiffness modulus (ITSM) and ultrasonic pulse velocity (UPV). While ITSM provided reference modulus values at strain levels and rates typical of traffic loads, UPV was used to estimate the Young modulus at very low strain levels and high frequencies.