Fundamental Studies on Styrene-Butadiene-Styrene Polymer Modified Road Bitumens

摘要

During the last two decades, road structures have deteriorated more rapidly thanexpected due to increases in traffic density, axle loading and tyre pressure and an insufficient degree of maintenance. To counteract the deterioration of road structures, the use of polymer modified bitumens has proved to be effective. The thesis consists of a literature review and experimental studies on styrene-butadiene-styrene (SBS) copolymer modified bitumens. In the literature review, basic aspects of bitumen chemistry and the rheology and characteristics of the polymers used for bitumen modification are described. A general compilation of test methods and specifications for SBS modified bitumens are presented. In addition, functional properties and field performance of SBS modified asphalt are briefly reviewed. The experimental part deals with studies on five bitumens from four sources modified with two SBS polymers at different polymer contents. Certain fundamental properties (e.g. compatibility, storage stability, temperature susceptibility and viscoelastic properties) of the modified binders are investigated using fluorescence microscopy and dynamic mechanical analysis, as well as conventional binder test methods. Chemical characteristics of base bitumens and SBS polymers are determined using Thin Layer and Gel Permeation Chromatography (TLC and GPC), respectively.