Improving the accuracy of mineral aggregate surface energy estimation based on goniometry

Goniometry is a low time-consuming technique used to determine contact angle of a variety of surfaces, which can be related to surface energy of materials and, therefore, to moisture susceptibility of asphalt mixtures. Given the importance of the technique, due to simplicity and wide range of applicability, it is essential to obtain reliable data, mainly for heterogeneous, rough surfaces, such as mineral aggregates. For this reason, this study focuses on reducing variability of contact angle data for surface energy determination of mineral aggregates, by controlling surface preparation, performing corrections due to surface roughness, reaching and measuring quasi-equilibrium for each drop. Based on factorial analysis, it was found that the factors that have a greater effect on contact angle values are the type of mineral aggregate and variables affecting the surface preparation of the samples. This study helps to ensure a more accurate determination of surface energy in mineral aggregates by means of goniometry.