Triaxial Testing for the Short Term Evaluation of Cold-Recycled Bituminous Mixtures

The experimental investigation described in this paper refers to the performancerelated characterization of cold-recycled bituminous mixtures employed for the construction and maintenance of road pavements. One of the most critical issues that have to be examined for these mixtures is their short term behaviour under loading, since in the early phases after laying they are more similar to unbound granular materials than to traditional hot bituminous mixtures. In such a context, the authors carried out triaxial tests on a reference cold-recycled mixtures by employing the equipment generally recommended for subgrade soils and foundation materials. Slender laboratory compacted specimens, prepared by means of a gyratory shear compactor, were subjected to triaxial tests for the determination of resilient modulus and of shear strength parameters at three different temperatures (20, 40 and 60°C) and in three different curing conditions (short term, intermediate and full curing). The obtained results were analyzed according to models already available in literature and were discussed by taking into account the internal structure and composition of the mixture.