Polymer modified asphalt binders

http://www.diva-portal.org/smash/get/diva2:711917/FULLTEXT01

Polymer modification of bitumen : Advances and challenges

1.Introduction to Composite Materials 2. Macrochemical Behavior of a Lamina 3.Micromechanical Behavior of a Lamina 4.Macromechanical Behavior of a Laminate 5.Bending, Buckling, and Vibration of Laminated Plates 6.Other Analysis and Behavior Topics 7.Introduction to Design of Composite Structures Appendix A.Matrices and Tensors Appendix B.Maxima and Minima of Functions of a Single Variable Appendix C.Typical Stress-Strain Curves Appendix D.Governing Equations for Beam Equilibrium and Plate Equilibrium, Buckling, and Vibration Index

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Mechanics of composite materials

Morphology, rheology, and physical properties of polymer-modified asphalt binders

The use of polymer modified asphalts for waterproofing and in road pavement has been continually increasing worldwide, because a relatively small quantity of added polymer can significantly enhance performance and durability. The knowledge of the morphological structure of such materials is still incomplete and controversial, mainly because of the compositional complexity. In practice, rheology is one of the most useful tools for the study of polymer modified asphalt. Particularly, nonlinear rheology may give unique information that helps to interpret how the polymer organizes when it is blended with asphalt. In this paper, besides a brief description of linear rheological properties and modeling, particular attention is paid to the most recent studies on the structure and to material functions, such as shear viscosity and relaxation modulus in the nonlinear viscoelastic region. The correlation of nonlinear behavior with polymer characteristics and with the architecture established when polymers are blended with asphalts is then described.

Relation between polymer architecture and nonlinear viscoelastic behavior of modified asphalts

The styrene-butadiene-styrene ~SBS! triblock copolymer was used to modify the asphalt binder. The morphology and engi- neering properties of the binders were investigated using transmission electron microscopy ~TEM!, rotational viscometer, and dynamic shear rheometer. The morphology of polymer-modified asphalt was described by the SBS concentration and the presence of microstructure of the copolymer. When the SBS concentration increased, the copolymer gradually became the dominant phase, and the transition was followed by a change in engineering properties of SBS-modified asphalt. Results from TEM showed that depending on the asphalt and copolymer source, a variety of morphology can be found. The SBS-modified binders might show a continuous asphalt phase with dispersed SBS particles, a continuous polymer phase with dispersed asphalt globules, or two interlocked continuous phases. The optimum SBS content was determined based on the formation of the critical network between asphalt and polymer. Because of this network formation, the binders showed a large increase in the complex modulus that indicates resistance to rutting. At low SBS concentrations, the Kerner model was found to be appropriate to estimate the rheological properties of SBS-modified asphalt. An adapted Kerner equation was proposed in this study to predict the complex modulus of modified asphalt at high SBS concentrations.

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Ming Shen Shiah

Papers

Asphalt modified by styrene-butadiene-styrene triblock copolymer: Morphology and model