Adhesion evaluation between asphalt and geosynthetic layers using microscopy technics
Maria das Graças Gardoni Almeida1; Karla Balzuweit1; Fernanda Taysa de Castro Morais1
1 Universidade Federal de Minas Gerais
Resumo
Geossynthetics have been commonly used as asphalt reinforcement during new pavement construction or overlay in order to form an anti-reflective cracking interlayer. Asphalt coat is usually applied at the interface to ensure proper bond between layers, being tack coat type (e.g. RR-1C) and application rate critical parameters to guarantee an acceptable adhesion between layers. Scanning electron microscopy was the technique used to analyze adhesion between asphalt and geosynthetic layers. Asphalt samples reinforced with geosynthetic and previously submitted to bending test were analyzed by scanning electron microscopy with the purpose of a better understanding of bending and shear effects. This work aims to define the most appropriate way to prepare samples of a highly heterogeneous material, reinforced asphalt concrete. The images obtained via SEM showed that geosynthetic fibers are not always perfectly covered with asphalt binder. Moreover, the reinforcement layer has porosity that can difficult the traffic load distribution, which may be an indication of decreased shear strength in asphalt layers reinforced with geosynthetic. Materials of construction have properties that are highly influenced by its own microstructure. Strength, toughness, and high/low temperature behavior are some examples of physical properties that can be changed if materials show microstructural defects. Microscopy techniques are therefore a powerful tool that helps scientists understand different and, in many cases, controversial behavior of materials. Asphalt concrete is one of the most used materials of construction in the whole word and its constituent materials have been analyzed by several microscopy techniques. Loeber et al. (1996) analyzed samples of asphalt binder utilizing scanning electron microscopy and also atomic force microscopy; their work included developing sample preparation of asphalt binder. Samples of unmodified and modified asphalt binders containing polyphosphoric acid were studied by surface (microscopy) tech
Palavras-chave: Reinforcement with geosynthetics; Adhesion between asphalt layers and Geosynthetics; Microscopy