Characterization of bitumens modified with SEBS, EVA and EBA polymers
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A laboratory evaluation of the modified bitumens containing styrene-ethylene-butylene-styrene (SEBS), ethylene vinyl acetate (EVA) and ethylene butyl acrylate (EBA) copolymers is presented. The morphology, storage stability and rheological and ageing properties of the modified binders were studied using fluorescence microscopy, dynamic mechanical analysis, creep test (bending beam rheometer) and conventional methods. The results indicated that the morphology and storage stability of the modified binders were largely dependent on the polymer content and were influenced by the characteristics of the base bitumens and the polymers. At a low polymer content (3% by weight), the modified binders showed dispersed polymer particles in a continuous bitumen matrix. At a sufficiently high polymer content (6% by weight), a continuous polymer phase was observed. Regardless of the nature of the two phases, the storage stability of the modified binders decreased as polymer content increased. Polymer modification improved bitumen rheological properties such as increased elastic responses at high temperatures and reduced creep stiffness at low temperatures. The degree of improvement generally increased with polymer content, but varied with bitumen source/grade and polymer type. Polymer modification also influenced bitumen ageing properties. Evaluation of ageing effect was dependent on testing conditions (e.g. temperature and frequency).
KeywordsBitumen Dynamic Mechanical Analysis Storage Stability Disperse Polymer Polymer Content
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- 1.J. F. Branthaver et al., “Binder Characterization and Evaluation, Vol 2: Chemistry, ” SHRP-A-368 (National Research Council, Washington, DC, 1993).Google Scholar
- 2.U. Isacsson and X. Lu, Materials and Structures 28 (1995) 139.Google Scholar
- 3.X. Lu Idem., ibid. 30 (1997) 618.Google Scholar
- 4.X. Lu Idem., Construction and Building Materials 11 (1997) 23.Google Scholar
- 5.H. U. Bahia, D. A. Anderson and D. W. Christensen, Proceedings of the Association of Asphalt Paving Technologists 61 (1992) 117.Google Scholar
- 6.D. Whiteoak, in “The Shell Bitumen Handbook” (Shell Bitumen, UK, 1991) p.74.Google Scholar
- 7.N. W. Mcleod, Proceedings of the Association of Asphalt Paving Technologists 41 (1972) 424.Google Scholar
- 8.X. Lu, PhD thesis, TRITA-IP FR 97–30, Royal Institute of Technology (KTH), Sweden, 1997.Google Scholar
- 9.H. U. Bahia and D. A. Anderson, in “Physical Properties of Asphalt Cement Binders, ASTM STP 1241, ” edited by J. C. Hardin, (American Society for Testing and Materials, Philadelphia, 1995) p. 28.Google Scholar