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The purpose of this work was to study the use of accelerometers to measure pavement deflections due to traffic loads. To this end, accelerometers were embedded in two sites: the full scale load simulator Circular Test Track (CTT) and the A1 motorway in Switzerland. Deflections were derived from acceleration measurements using an algorithm that double integrates the measured signal and corrects any errors derived from the procedure. In the motorway, deflections were monitored using a set of three magnetostrictive deflectometers. Additionally, the pavement's material viscoelastic parameters determined in the laboratory were incorporated in Finite Element (FE) models to estimate the theoretical deflections. The calculated deflections were then compared to the measured and to the theoretical deflections. Deflections calculated from acceleration showed a reasonable qualitative correlation to those measured by magnetostrictive deflectometers. In addition, the FE models revealed the inability of the accelerometers to measure very slow or quasi-static motion.

The fatigue of asphalt mixes constitutes one of the main types of distress of pavement structures. In laboratory, different procedures and testing equipments were implemented to describe the fatigue properties of asphalt mixes. Among them, the repeated indirect tensile test is used to determine the fatigue properties of asphalt mixes and also, their resilient modulus. Generally, fatigue tests are conducted using one of the two basic types of loading: controlled-strain or controlled-stress. Both loading modes produce fatigue prediction models relating the initial response (tensile strain or stress) of asphalt mixture to the fatigue life. In recent years, the application of more fundamental approaches has been suggested. One of these approaches is based on the principles of the Fracture Mechanics. The most popular relationship used in fracture mechanics is the Paris´ law. This paper presents an application of the Repeated Indirect Tensile Test to determine the fundamental parameters governing the crack propagation process in asphalt mixtures. The basic adopted hypotheses, the used data reduction techniques and the results obtained for an asphalt mixture considered as an example are presented, discussed and compared with other cited in the analysed literature.

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