Comprehensive evaluation on the mechanical behaviour of cement-bitumen treated materials

Cold recycling techniques combine environmental and economic advantages. The development and improvement of both binders and construction equipments allow using cold recycled mixtures without reducing the pavement performance, or complicating the management of production plant or in-filed works. For these reasons, cold recycling has been considered in many countries as a common construction technique and no longer as an alternative technique to the traditional ones. However, the difficulties in simulating the production and construction processes in laboratory have led researchers to practise full-scale testing of mixtures. This paper presents a comprehensive evaluation of the mechanical behaviour of a cement-bitumen treated mixture (CBTM) containing 80 % of Reclaimed Asphalt (RA). After a preliminary mix design in laboratory, the selected mixture was produced in a mix plant and laid down on two trial sections with two different CBTM thicknesses (15 and 20 cm) over an homogeneous subgrade. The mixture was sampled before laying, compacted by means of a gyratory compactor and characterized through indirect tensile test and indirect tensile stiffness modulus test. Moreover, the same tests were carried out on cores taken from the trial sections. Lightweight deflectometer and falling weight deflectometer surveys were performed on the trial sections to evaluate the curing process of the layer.