Avaliação do processamento digital de imagens como ferramenta para caracterização de agregados e misturas asfálticas

Abstract

It is a general consensus that the mechanical performance of asphalt mixtures with respect to the pavements’ main distresses (permanent deformation, fatigue cracking and thermal cracking) is directly related to the aggregates’ properties used in those mixtures. The traditional methodology of characterizing aggregates, mainly in relation to shape properties, such as form, angularity and texture, can be very time-consuming. It also does not provide precise results, because it combines more than one property in a single test result. Another disadvantage is the fact that these methodologies also provide average values that may not represent well the evaluated materials. There are alread y in the literature several Digital Image Processing (DIP) techniques that can be used with the purpose of characterizing aggregates in a more complete and realistic way. One of them is the Aggregate Image Measurement System (AIMS), equipment developed to analyze properties, such as: shape, angularity, and superficial texture of coarse and fine aggregates, through different methods. It is believed that different quarries can produce aggregates with very distinct properties, due to the several used rock blasting and crushing processes, quality control activities and material storage methodology. The main objective of this research is to evaluate the potential use of DIP to analyze shape, angularity and texture of aggregates from different sources and to analyze asphalt mixtures internal structure constituted by those aggregates. Aggregates from three different quarries, all located in the State of Ceará, were obtained and characterized. The aggregates were analyzed using AIMS, for different sizes, and the results were compared. Besides that, the asphalt mixtures constituted with these aggregates were analyzed regarding their internal structure and their mechanical characteristics. The main results obtained in this study led to conclude that the aggregates used in this research are very similar in respect to their form, angularity and texture properties. With respect to the mechanical properties of the mixtures constituted by these aggregates, the results show that their behavior is also very similar, which is probably due to the similar characteristics of their aggregates.