Cracks in rigid pavements are a frequent and critical problem, which needs to be assessed to avoid deterioration and provide comfort and security. Control of damage requires the evaluation of cracks width and depth. Several laboratory tests were used in order to determine the ability of Ground Penetrating Radar (GPR) in the evaluation of damage under different controlled conditions. Those tests were focused in the analysis of different crack dimensions, changing the material inside the fractures and the orientation of the antenna with respect the crack axis. Results showed that the crack width increases hyperbolae amplitude, being the thinnest crack detected with a 2.3 GHz antenna, 2 mm thick. GPR B-scans were compared to images from computational models. Additionally, a field survey provided images according to the lab tests.

One of the most important steps in the rehabilitation of flexible pavements is the evaluation of their bearing capacity, which is used to assess the moduli of the pavement layers. The evaluation of the bearing capacity is usually carried out by measuring pavement deflections using a Falling Weight Deflectometer (FWD). This evaluation is undertaken in equally spaced points, usually 100 metres apart, with temperature variations throughout the day. Due to the viscoelastic behaviour of the asphalt layers, these FWD measurements are influenced by the pavement temperature, and the moduli can only be compared if they correspond to the same temperature. Thus, this work develops a model to adjust the pavement deflections to a reference temperature based on the characteristics of the pavement; namely: the asphalt layer thickness, subgrade stiffness, the distance between the FWD sensors, the load magnitude, and the pavement temperature.

The use of crumb rubber in the modification of asphalt has occurred because of the problems related to disposal of scrap tires. However, the use of scrap tires in asphalt pavements, known as asphalt rubber pavements, can minimize environmental impacts and maximize conservation of natural resources. The textile fibers from recycled tires are typically disposed of in landfills or used in energetic valorization, but similar to other fibers, they can be used as a valuable resource in the reinforcement of engineering materials such as asphalt mixtures. Thus, this work aims at studying the use of textile fibers recycled from ground tires in the reinforcement of conventional asphalt mixtures. The application of textile fibers from ground tires was evaluated through laboratory tests on specimens extracted from slabs produced in the laboratory. Indirect tensile tests were performed on a series of nine asphalt mixtures with different fiber and asphalt contents and compared with a conventional mixture. The results obtained from a 50/70 pen asphalt were used to define three asphalt mixture configurations to be used with 35/50 pen asphalt. The results indicate that the textile fibers recycled from used tires can be a valuable resource in the reinforcement of asphalt mixtures.