Experience with semi-open graded asphalt surfacings in South Africa

This paper describes the authors’ experience with Semi-Open graded Bitumen-Rubber Asphalt (BRASO) wearing courses on heavily trafficked pavements where superior long-term structural and functional performances were required. The benefits in using these mixes on heavily trafficked roads are their superior fatigue, plastic deformation and binder ageing resistance that result in wearing courses that outperform more conventional asphalt mixes. Bitumen Rubber Asphalt (BRA) has been used successfully in South Africa since the mid 1980’s. This paper describes the materials, the mixing process, mix characteristics, practical matters relating to the design, construction and post-construction performance of BRA wearing courses used in four projects in Gauteng Province, South Africa. The wet method was used on two of the projects with the dry process on the other two, for the production of the BRASO. Stricter quality control procedures on BRASO mixes, although initially considered to be cumbersome, proved to be essential to ensure consistent and acceptable mixes. Stringent monitoring of binder viscosity, digestion period and mixing temperatures, as well as the storage and binder content itself, proved to be crucial for the successful construction of BRASO wearing courses. The differences in approach by following the wet and dry methods with respect to mix design, construction and quality control of BRASO mixes are described in the following paper. The paper concludes with the identification of areas where improvements are still required.

• Record URL:
  http://arrbknowledge.com
• 
• Authors:
  • Balmaceda, P
  • van Wijk, I
• Conference:
  • AAPA International Flexible Pavements Conference, 15th, 2013, Brisbane, Queensland, Australia
• Publication Date: 2013-9

Language

• English

Media Info

• Pagination: 17p
• Monograph Title: Delivering new age solutions: 15th AAPA International Flexible Pavements Conference, 22-25 September, Royal International Conference Centre, Brisbane

Subject/Index Terms

• TRT Terms: Bituminous materials; Crumb rubber; Mix design; Pavement design; Pavement performance; Quality control; Rubber; Surfacing; Viscosity
• Uncontrolled Terms: Pavement technology
• Geographic Terms: South Africa
• ATRI Terms: Crumb rubber; Mix design; Pavement design; Pavement performance; Quality control; Viscosity
• Subject Areas: Highways; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 01503282
• Record Type: Publication
• Source Agency: ARRB
• Files: ITRD, ATRI
• Created Date: Jan 6 2014 10:55AM