Ground Penetrating Radar (GPR) is a prospecting method frequently used in monitoring asphalt pavements, especially as an optimal complement to the defection test that is commonly used for determining the structural condition of the pavements. Its application is supported by studies that demonstrate the existence of a relationship between the parameters determined in GPR data (usually travel time and wave amplitude) and the preservation conditions of the structure. However, the analysis of frequencies is rarely applied in pavement assessment. Nevertheless, spectral analysis is widespread in other fields such as medicine or dynamic analysis, being one the most common analytical methods in wave processing through use of the Fourier transform. Nevertheless, spectral analysis has not been thoroughly applied and evaluated in GPR surveys, specifically in the field of pavement structures. This work is focused on analyzing the behavior of the GPR data spectra as a consequence of different problems affecting the pavement. The study focuses on the determination of areas with failures in bituminous pavement structures. Results epitomize the sensitivity of frequencies to the materials and, in some cases, to the damage.

Manuscript Code: 479Date of Reception/Aceptance: 01OCT2014/01APR2015 Resumen El principal objetivo de este estudio es presentar una nueva metodología para caracterizar la capacidad adhesiva (capacidad conjunta de cohesión y adhesión) de los cementos asfálticos mediante nuevos parámetros mecánicos. Esta nueva metodología está basada en el ensayo Fénix, desarrollado recientemente en España. Este método permite evaluar la resistencia a fisuración de las mezclas asfálticas, pero ha sido modificado para caracterizar el poder adhesivo de los cementos asfalticos. Los principales parámetros obtenidos están relacionados con la energía disipada en la ruptura de los puentes de adherencia entre el árido y el ligante cuando estos materiales están sometidos a esfuerzos de tracción. Los resultados de la fase experimental de investigación son presentados en este artículo, los cuales derivan de la aplicación de la nueva metodología propuesta para evaluar el comportamiento del cemento asfáltico en la matriz árido-ligante de acuerdo a la variación de la temperatura, el efecto del agua y el envejecimiento, tomado en cuenta áridos del mismo origen, pero diferente forma geométrica. Los resultados obtenidos muestran que la metodología propuesta permite caracterizar la capacidad adhesiva de los cementos asfálticos para las condiciones evaluadas.Palabras clave: Ligante de asfalto, aglomerante de agregado ligante, capacidad adhesiva, ensayo Fénix. AbstractThe main goal of this study is to present a new methodology to characterize the adhesive capacity (cohesion and adhesion capacity) of asphalt binders by means of new mechanical parameters. This methodology is based on the Fenix test, a test recently developed in Spain. This method assesses the cracking resistance of the asphalt mixtures, and it has been adapted to characterize the bonding power of asphalt binders. The main parameters achieved with this procedure are related to the energy dissipated during the breaking between the asphalt binder and the aggregate, when these materials are subjected to tensile stress; essential parameters related to the adhesive capacity of asphalt binders. The results of an experimental stage are presented in this research, in which the proposed methodology has been applied to analyse the behaviour of the binder in the aggregate-binder matrix according to temperature variation and the effect of water and ageing; taking into account aggregates of the same origin and with a different shape pattern. The results show that the parameters achieved from this new methodology allows characterizing the adhesive capacity of asphalt binders in the different conditions assessed.