The purpose of this study was to evaluate the Young's modulus of cold and warm gutta-percha. Rods of gutta-percha. Specially designed by three companies were tested at 20 degrees C and 55 degrees C with a tensile testing machine. The Young's modulus, the yield strength and the percentage of deformation were automatically recorded. There was a statistically significant difference, for the three criteria, between the cold and warm gutta-percha. Warm gutta-percha presented a Young's modulus 100 times smaller, a yield strength 2 times smaller but a percentage of permanent deformation 10 times higher than cold gutta-percha. Gutta-percha Hygenic presented the best characteristics.

The current concern for the environment and the need to reduce greenhouse gas emissions have led to new technologies related to microwave energy. One of these technologies is the self-healing of asphalt mixtures, which consists of repairing pavements through microwave application on the surface, avoiding premature road failure. Asphalt mixtures for roads are made up of more than 90% by weight of aggregates of different compositions and origins, in addition to a bituminous binder and sometimes additives. From other studies, it is known that the physical behaviour of aggregates is a function of their composition, that is, of their minerals and their proportions. Microwave heating of aggregates has proven to be an effective technique, but there are gaps in understanding how microwaves interact with aggregates and the reasons for their differential heating. This research has studied 18 minerals that are commonly part of the rocks used as road aggregates. The objective is to identify the minerals that present the best heating rates to relate them to the differential heating of aggregates for roads. The results obtained are promising, facilitating the understanding of microwave heating of minerals. Regarding chemical composition, elements such as MgO, MnO, TiO, Al2O3, Fe2O3, and CaO (in silicate minerals) favour the heating of minerals and other elements such as SiO2 and K2O Na2O, and CaO (in carbonate minerals) retard the heating. Regarding the physical properties, density and habit of the minerals do not influence the heating, but other properties, such as the diaphaneity and the size of the crystals, influence the heating with microwaves.