Rheological characteristics of South African bitumen

Bitumen is one of the major material components in road surfacings. It acts as the binder that holds the aggregates together and provides adhesion between the surfacing layer and the base. The aggregates provide the abrasion resistance and the bitumen the waterproofing. Bitumen provides the viscoelastic characteristics to these materials allowing the seal to respond to traffic loading without stripping, and to respond to the top pavement deflection and cracking. The performance and life of the road depends on the response of the material to the traffic loading and environmental forces. To understand and predict the behaviour of bitumen, these characteristics must be measureable. Viscoelastic parameters of bitumen such as the complex modulus and the phase angle characterise the material response to dynamic loading and are key elements in understanding of the performance of bituminous materials. The Dynamic Shear Rheometer (DSR) test is listed as one of the methods for measuring the viscoelastic characteristics of bitumen in the laboratory. This paper presents material response models of four South African bitumens namely: 70/100 penetration grade, SE1 Polymer modified bitumen, SR1 bitumen rubber and SCE1 emulsion modified bitumen. This paper uses data collected from DSR tests to develop a mathematical viscoelastic model and a mechanical viscoelastic model. The mathematical model is based on master curves constructed using the Time Temperature Superposition Principle (TTSP) and Christensen–Anderson principle. The mechanical model is based on the “spring–dashpot” principle and is presented by Prony series, Huet-Sayegh and 2S2P1D models. The establishment of the response models of the various bitumens could allow the development of mechanistic analysis of seals expressed in terms of stress-strain interactions. This mechanical analysis, expressed as Finite Element modelling of seal, is part of subsequent study under development not presented in this paper.

Language

  • English

Media Info

  • Pagination: 11p
  • Monograph Title: 11th Conference on Asphalt Pavements for Southern Africa: CAPSA15, 16-19 August 2015, Sun City, South Africa

Subject/Index Terms

Filing Info

  • Accession Number: 01597103
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Apr 22 2016 11:14AM