Showing papers by "Hugo Manuel Ribeiro Dias da Silva published in 2003"

Comparison between tensile, stiffness and fatigue life tests results

Abstract: A laboratory mechanical test is being implemented in the University of Minho to evaluate the asphalt/interaction. This test measures the tensile properties of the bituminous mixture in the interface between the asphalt and the aggregates. By using the tensile test it is intended to observe how the asphalt-aggregate interaction influences the mechanical properties of the bituminous mixtures, namely, stiffness modulus and fatigue life. The tensile test results must have a good correlation to the ones of the stiffness and fatigue life tests in order to assure that the tensile test can be used to investigate the influence of the asphalt-aggregate interaction in the mechanical behaviour of the bituminous mixtures. Thus, this paper presents the comparison between the tensile strength results and the fatigue life and stiffness modulus results of the corresponding mixtures. For the covering abstract see ITRD E117423.

Evaluation of the bond between mastic and coarse aggregates

Abstract: In the last decades, the flexible road pavements have been subjected to the action of a more intense traffic, which has often originated their premature degradation. Among others, to guarantee a better performance of the pavement, it is essential that the bituminous mixtures show an appropriate behavior in situ for the high solicitations to which they will be submitted. The bituminous mixtures behavior is evaluated through tests that allow the study of their properties. The bond between the mastic and the coarse aggregates may possibly influence the behavior of a bituminous mixture in the pavement. Thus, the main aim of this work was the study of the bond between mastic and coarse aggregates, trying not only to contribute to a better knowledge of this property, but also to a better behavior of the bituminous mixtures in situ. A proceeding to study the mastic composition was developed and mechanical tests were used in order to evaluate the bond between mastic and coarse aggregates, which is determined through the tensile and shear strengths. The results of the mechanical tests were used to evaluate the influence of the mastic binder content on the strength of the bond between mastic and coarse aggregates. In the same tests, it was also observed the main type of failure of the bond between mastic and coarse aggregates.

The influence of fine aggregate on the bituminous mixture mechanical behaviour

Abstract: The mechanical behaviour of a bituminous mixture is influenced by its composition. One of the compositional parameters that can change the bituminous performance in a pavement is the gradation of the fine aggregates. This paper presents the stiffness, fatigue and permanent deformation results of bituminous mixtures used in wearing and base courses. For each type of mixture, five mixtures were defined, by changing the gradation curve (from more to less fine aggregates). All mixtures were produced and compacted in the laboratory. Specimens for tests were obtained by cored and sawed from compacted slabs. For stiffness and fatigue, tests were executed on four point bending beam on controlled strain, whereas for permanent deformation, tests were the repetitive simple shear test at constant height. For the covering abstract see ITRD E117423.