A Contribution to couple aging to hot mix asphalt (HMA) mechanical characterization under load-induced damage

• Ano de defesa: 2014
• Autor(a) principal: Babadopulos, Lucas Feitosa de Albuquerque Lima
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Palavras-chave em Português: Transportes; Misturas de emulsão asfáltica; Fadiga; Deformabilidade
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/11164

Although aging simulation in binder is performed through RTFO and PAV tests, n o considerations of asphalt mixture aging are made in regular laboratory characterization. T he present work is focused in incorporating aging to the modeling of the mechanical behavior of hot mix asphalt (HMA) during load - induced damage. This is accomplished by combining existing models and the adaptation of mixture aging procedures . The aging model used is based on the evolution of an internal state v ariable, associated to oxygen availability, aging temperature a nd four material parameters. The se parameters are related to aging susceptibility , reaction kinetics and dependency on aging history and on aging temperature. The model allows to establish relation ship s between different aging processes. Results at four aging states (using two different temperatures) we re analyzed and the aging model parameters w ere estimated. Capturing aging dependency on temperature constitutes a contribution of the presen t work with respect to previous results reported in the literature . T he aging model is coupled to viscoplasticity and damage, comparing the behavior observed at the different aging states. Concerning the damage models, t his thesis used mechanical models de rived from Schapery's work potential theory to model fatigue behavior . T he Simplified Viscoelastic Continuum Damage (S - VECD) model was selected . U nconfined dynamic creep tests were used to evaluate the effect of aging in the mixture resistance to permanent deformation. In addition to the state - of - the - art modeling of HMA, the characterization methods currently in use in Brazil (tensile strength, resilient modulus and controlled force indirect tensile fatigue tests) were also conducted . T he possibility to sim ulate the material behavior for various loading conditions constitutes a n advantage of the state - of - the - art model over the state - of - the practice method for fatigue characterization, used primarily to rank mixtures. It was concluded that, depending on pavem ent conditions and layer geometry, aging not necessarily affects negatively the fatigue behavior, while certainly improving the permanent deformation characteristics. That happens de s pite the fact that aging produces less damage tolerant materials, i.e., m aterials that fail for less evolved damage states. T he framework ( testing and analysis) for damage characterization of asphalt mixtures was implemented and it is expected to contribute to further developments in aging modeling of asphalt mixtures