STRAIN ABSORBING ASPHALT WEARING COURSE. DURABILITY AND PERFORMANCE OF BITUMINOUS HIGHWAY MATERIALS, HATFIELD POLYTECHNIC, 3-4 APRIL 1989
This paper describes overlay strengthening works where the properties of the binder used in the wearing course have been modified to provide improved strain characteristics. A full scale trial has been carried out on the a508 in England to compare the properties of binders and their ability to accept strain movements whilst retaining performance requirements. Sbs, (styrene butadiene styrene) Trinidad lake asphalt (tla) and refinery bitumen binders have been incorporated in these trials and their ability to perform over a range of temperature conditions is discussed. High temperature deformation of the asphaltic materials was examined by accelerated wheel tracking tests at 45 degrees C on core samples. Temperature susceptibility of the binders was assessed by measuring the soft point and penetration over a range of temperatures between 1 and 40 degrees C. Fraass brittle point was also determined. Repeated load indirect tensile testing and measurement of tensile breaking stress and strain at break were conducted between +20 and -10 degrees c. The results show that simple 'production control' tests such as penetration and softening point are insufficient indicators of binder performance especially at low temperatures where it is believed cracking is initiated. In order to fulfil engineering functions either the quality of the bitumen needs to be improved by enhanced specification or engineering tests on the complete bituminous mixture over a temperature spectrum adopted to provide serviceability performance. For the covering abstract of the conference see IRRD 823743.
Hatfield Polytechnic, EnglandSchool of Engineering, College Lane, P.O. Box 109
Hatfield, Hertfordshire, England
- BICZYSKO, S J
- Publication Date: 1989
- Pagination: 10 p.
- TRT Terms: Admixtures; Binders; Bituminous mixtures; Brittleness; Cracking; Deformation; Deterioration; Durability; Mix design; Pavements; Polymers; Rutting; Softening point; Strength of materials; Strengthening (Maintenance); Temperature; Tension; Trinidad asphalt; Wearing course (Pavements)
- Subject Areas: Highways; Pavements;
- Accession Number: 00498706
- Record Type: Publication
- Source Agency: Transport and Road Research Laboratory (TRRL)
- Files: ITRD, TRIS
- Created Date: Sep 30 1990 12:00AM