Evaluation of the specific surface method as a tool to determine the asphalt content of fine aggregate matrices (FAM)

• Autor(a) principal: Grasson Filho, Adrian
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/18/18143/tde-16122019-141054/
• topic: Asphalt Binder Content; Fine Aggregate Matrix; Matriz de Agregado Fino; Specific Surface; Superfície Específica; Teor de Asfalto

The studies of the Fine Aggregates Matrix (FAM) are able to provide important information about the fatigue behavior of the hot asphalt mixtures (HMA). Despite the increasing number of research works in this area, there is no consensus on the most appropriate method to estimate the asphalt binder content of the FAM and that represents the FAM fraction of the HMA mixture in a precise way. The method developed by Sousa et al. (2013) stands out among the methods available in the literature. It is an experimental method which calculates the asphalt binder content by mass difference. In spite of being a practical experimental method, the binder extraction by means of the ignition process might be a barrier for some laboratories. As any experimental method, the Sousa\'s method is also susceptible to the influence of the operator. In order to overcome these issues, the applicability of an analytical method, as proposed by Ng et al. (2018) and based on the specific surface concept of the mineral aggregate, was evaluated. In this experiment, three mineral aggregates (two granites and one basalt rock), four aggregate gradations and one asphalt binder (PG 70-16) were used. Concerning the Sousa\'s method, the results of this study showed the importance of taking into account the crystallization water of the mineral aggregate in order to obtain a more precise estimate of the FAM binder content. The specific surface method proved to be capable of producing a reliable estimate of the FAM binder contents, by taking the following aspects into account: (i) the estimate of the specific surface area of the filler by means of the laser diffraction method by using the Malvern Mastersizer 2000 (R² = 0.9948) and the sedimentation curve as per the Stokes law (R² = 0.8402), and (ii) the FAM richness modulus obtained by means of a relationship with the richness modulus of the HMA mixture developed in this study.