Optimization of BBR testing for low temperature behaviour

The bending beam rheometer (BBR) provides a more accurate quantification and assessment of the low-temperature behaviour of bitumen and polymer-modified bitumen than currently obtained with the Fraass breaking point test which has a low precision. Up to now this performance orientated test method has been applied in the USA and in several European countries. EN 14771 requires a testing load of 980 mN and a measurement of stiffness and m-value after 60 seconds loading time. These parameters and the testing temperature of -16 degreesC used in Germany do not allow a comprehensive assessment of the tested bitumen. At present a research project on 19 bitumens and polymer-modified bitumens is being carried out for the German ministry of roads. The tests are performed at four temperatures (-12, -16, -20 and -24degreesC) and with three different loads (780 mN, 980 mN, 1230 mN) to optimize the testing parameters of EN 14771. The chosen temperatures enable the investigation of temperature behaviour over a wide range. The variation of the load enables the coverage of the range of deformation experienced in practice. The evaluation of values for stiffness and m-value were calculated over the whole loading time. This procedure enables a more comprehensive assessment of different bitumen. The procedure used in the SHRP Program to find the temperature corresponding to a stiffness of 300 MPa was also carried out. For the covering abstract see ITRD E157233

• Authors:
  • STUETZ, M
  • WOERNER, T
  • WALLNER, B
• Publication Date: 2008

Language

• English

Media Info

• Pagination: 6p
• Serial:
  • PROCEEDINGS OF THE 4TH EURASPHALT AND EUROBITUME CONGRESS HELD MAY 2008, COPENHAGEN, DENMARK
  • Publisher: EUROPEAN ASPHALT PAVEMENT ASSOCIATION (EAPA)

Subject/Index Terms

• TRT Terms: Bitumen; Conferences; Deformation; Frost; Polymers; Sensitivity; Stiffness; Temperature; Test procedures
• ITRD Terms: 4963: Bitumen; 8525: Conference; 5595: Deformation; 2585: Frost; 7482: Polymer; 5928: Sensitivity; 5931: Stiffness; 6722: Temperature; 6288: Test method
• Subject Areas: Data and Information Technology; Hydraulics and Hydrology; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 01321309
• Record Type: Publication
• Source Agency: TRL
• Files: ITRD
• Created Date: Nov 29 2010 10:56AM