José Leomar Fernandes Júnior

Modelo de previsión de la progresión del área de fisuras en pavimentos asfálticos

This work presents the development of a model to predict cracking progression in hot-mix asphalt pavements, based on information obtained from a database maintained by State of Bahia Department of Transportation, with data collected in 2004. A factorial design was performed to arrange the data available in order to facilitate the statistical analysis. The factors considered were age of the pavement, traffic volume and rainfall. The model developed in this work to predict cracking progression was compared to other existing models through the evaluation of the fit to the observed data, based on its evolution over time. The performance model developed in this work was compared to performance models developed by Marcon (1996) and Paterson (1987) presented the best results, in an evidence of its applicability to other highway networks.

MINERAL FILLER INFLUENCE ON MASTIC FRACTURE ENERGY

The mechanical properties of asphalt mastic influence significantly the overall performance of hot mix asphalt. The behavior of the asphalt mastic influence almost every aspect of the design, construction, and performance of hot mix asphalt. The fatigue damage and fracture in the hot mix asphalt are strongly related to binder characteristics, filler properties, interaction between the binder and filler, and is a phenomenon affected by the development and growth of microcracks in the mastic. The mixture performance can be improved if the mastic is design to resist fracture and fatigue. Fracture energy is an important property related to fatigue resistance of binders and have a strong influence on the cracking performance of flexible pavement. A new binder fracture energy test was developed by Roque et al (2012) based on nonlinear 3-D Finite Element Analysis (FEA) to determination of stress and strain on the fracture plane, which in turn assures accurate determination of fracture energy. The study of the mastic behavior is important to evaluate the effects of the mineral filler amount and the asphalt binder properties, as well as the different filler types and nature effects, and evaluate its influence on the asphalt binder stiffness and elasticity, provided by the filler addition at different ratio filler/binder. The overall objective of this study was to determine the fatigue damage characteristics of asphalt binders and mastics by measuring the fracture energy. The addition of filler to the asphalt binder decrease the fracture energy value, compared to the pure asphalt binder, and as the filler amount increases, the fracture energy value decrease even more, including the Portland cement filler.

O EFEITO DA CARACTERIZAÇÃO DO TRÁFEGO NO DESEMPENHO DO PAVIMENTO FLEXÍVEL

A caracterizacao das cargas do trafego e de grande importância para o dimensionamento de pavimentos, bem como para a quantificacao do desempenho para fins de gerencia de pavimentos. Assim, o objetivo desta pesquisa foi analisar os efeitos da caracterizacao do trafego sobre o desempenho dos pavimentos, a partir da geracao de modelos estatisticos baseados no conceito proposto pelo metodo empirico-mecanistico da AASHTO, de espectros de carga por eixo dos veiculos comerciais de carga, comparando-os com o conceito de equivalencia de carga, desenvolvido a partir do AASHO Road Test. Dados de pesagens realizadas no ano de 2008 no Posto de Pesagem de Veiculos da SP-160, km 28, pista Sul, foram utilizados para o desenvolvimento dos espectros de carga e posterior modelagem. A comparacao entre os resultados previstos pelos modelos e os dados originais, feita tanto pela abordagem empirica como pela empirico-mecanistica, com uso dos programas computacionais ELSYM5 e MEPDG, evidenciou o modelo Weibull como o mais indicado para aplicacao em rodovias brasileiras com caracteristicas de trafego semelhantes as da Rodovia dos Imigrantes. Palavras-chave: veiculos rodoviarios, solicitacoes do trafego, carga por eixo, espectros de carga, desempenho de pavimentos. ABSTRACT The characterization of traffic loads is of great importance for pavement design, as well as for the measurement of performance in a pavement management system. Thus, the objective of this research was to analyze the effects of traffic characteristics on pavement performance through the generation of statistical models based on the concept proposed by the AASHTO mechanistic empirical method, axle load spectra of commercial vehicles, comparing them with the concept of load equivalence factor, developed through the AASHO Road Test. Data collected in 2008 in a weighing station located on Immigrant Highway, SP-160, km 28, southern runway, were used for the development of load spectra and subsequent modeling. The comparison between the results predicted by the models and the original data, made either by empirical and empirical-mechanistic approaches, with use of computer programs ELSYM5 and MEPDG, shows that the Weibull model is the most suitable for application in Brazilian highways with similar traffic characteristics to the Immigrants Highway. Keywords: road vehicles, traffic load, axle load, axle load spectra, pavement performance.