Polymer modified asphalt binders

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

Polymer modification of bitumen : Advances and challenges

Investigation of rutting performance of asphalt mixtures containing polymer modifiers

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

Effects of nanoclay on rheological properties of bitumen binder

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

Fatigue cracking is considered to be the primary failure mechanism that occurs at ambient temperatures in an asphalt pavement. The bituminous binder plays an important role in this failure mechanism, because fatigue cracking tends to take place predominately within the binder itself. Oscillatory tests using a dynamic shear rheometer (DSR) and wheel tracking fatigue tests were carried out on a wide range of bitumen-filler mastics and on asphalt mixtures containing the corresponding mastics to investigate their fatigue relationships. The addition of the mineral filler to bitumen was found to have a significant influence on the fatigue life of mastic owing to the stiffening effect and the filler particles interrupting the crack growth in the mastic. The results of stiffening ratio showed that the 65% mastics were in the concentrated suspension region, whereas the 35% mastics were in the dilute suspension region. In terms of shear stress, the fatigue order was 40/60 pen bitumen followed by 35% mastic,...

Fatigue Characteristics of Bitumen-Filler Mastics and Asphalt Mixtures

Polymers are increasingly being used to modify asphalt and enhance highway pavement performance. This paper reports the development of a procedure to evaluate and optimize a polymer-modified asphalt (PMA). Two asphalt cements and two styrene-butadiene-styrene (SBS) copolymers were mixed at ten concentration levels. The engineering properties and morphologies of the binders were investigated using a dynamic shear rheometer, scanning electron microscopy (SEM), and other rheological techniques. The morphology of the PMA was characterized by the SBS concentration and the microstructure of the copolymer. Polymer modification increased the elastic responses and dynamic moduli of asphalt binders. As the SBS concentration increased, the copolymer gradually became the dominant phase, accompanied by a change in engineering properties. Results from SEM demonstrated that, up to 6% concentration, good compatibility exists between SBS and asphalt binder. The modified binders show either a continuous asphalt phase with dispersed SBS particles or a continuous polymer phase with dispersed asphalt globules, or two interlocked continuous phases. The optimum SBS content was determined based on the formation of a critical network between asphalt and polymer.

Evaluation and optimization of the engineering properties of polymer-modified asphalt

There has been an increasing awareness of the addition of ordinary Portland cement (OPC) rather than limestone filler into asphalt pavements in Taiwan. Filler interpaticle interaction and physicochemical interaction between cement filler particle and asphalt improved engineering properties of asphalt mixtures. Current Superpave parameters of G*/sinδ and G*sinδ were used to link the rheological properties of asphalt binders to the pavement performance of rutting and fatigue. However, the characteristics of asphalt binders were determined in the linear viscoelastic domain by performing frequency sweeps. The asphalt binder film might perform in the non-linear range due to the considerable difference between the stiffness modulus of aggregates and the modulus of binders. In addition, the filler-asphalt interaction might not be reflected by means of the Superpave parameters. Mechanical properties of stiffness, deformation and fatigue for filler-asphalt mastics may be more appropriate in terms of establishing a correlation with asphalt pavement performance. Oscillatory and creep tests using a dynamic shear rheometer (DSR) were performed to quantify the mechanical properties of cement and limestone filler-asphalt mastics at the same levels of filler contents by weight. The test results showed that the higher complex modulus and stiffening effect of the cement filler-asphalt mastics than those of the limestone filler-asphalt mastics within a linear viscoelastic domain. In terms of creep behavior, the addition of cement filler to base bitumen increases the viscosity at a steady state. The longer fatigue lives for the cement filler-asphalt mastics indicated the addition of active filler may provide a better pavement durability.

http://www.ijprt.org.tw/reader/pdf.php?id=348

Min Chih Liao

Papers

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

Fatigue Characteristics of Bitumen-Filler Mastics and Asphalt Mixtures

Evaluation and optimization of the engineering properties of polymer-modified asphalt

Mechanical properties of filler-asphalt mastics

Evaluation of internal resistance in hot-mix asphalt (HMA) concrete