Bituminous stabilised materials: comparative performance of G2 and BSM-foam bases

The growth in-situ and in-plant recycling units provides evidence of the global increase in application of bitumen stabilisation technology in the rehabilitation of road pavements. Application of the technology has varied regionally and continentally, in terms of mix composition, binder types and application and climatic conditions. So too has the research varied, yielding different mix design methods and structural evaluations procedures. In South Africa the vast majority of national roads are constructed with highly compacted granular bases, G1 and G2 in terms of specification, with a stabilised subbase as support. As these pavements near the end of their structural lives a viable rehabilitation strategy is to inject new life into the base by bitumen foam stabilisation. At the same time, the sophistication of laboratory equipment has facilitated more detailed evaluation of material behaviour and performance. This paper uses triaxial testing with advanced instrumentation, to establish the strength (shear parameters), response properties (resilient modulus) and damage properties (permanent deformation) of bitumen stabilised material (BSM). BSM mix compositions typical of southern Africa are used i.e. comprising 2.4% bitumen and 1% cement are evaluated. The procedure followed in this study was to do triaxial testing on a well-graded, highly compacted granular (G2) material. The same specimens were then stabilised with a bitumen foam process and subjected to the same test regime as the granular material. This allowed the comparison of the granular and foam treated materials’ performance. The primary objective of the study is to compare the performance of a granular material and the foam stabilised version of the same material to mimic an actual real life situation where a road base is initially constructed with a granular material and then, after reaching its structural life, is bitumen-foam stabilised to extend the pavement life. Results of the study show that the pavement life can be extended with at least the same as the original life. This enables the true benefit, or otherwise, of the bitumen stabilisation to be evaluated.


  • 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: 01597117
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Apr 22 2016 11:15AM