A SIMPLE GUIDE TO VISCOSITY AND RHEOLOGY

The viscoelastic properties of bitumens directly and significantly affect the performance of mixtures comprising bitumen as a binder. This paper summarises some of this knowledge, which is needed to ensure good long-term performance when designing such mixtures. Viscosity can be defined as the extent to which a fluid material resists the tendency to flow, and determines how it will behave over a given temperature range. The two types of viscosity measured are kinematic viscosity and dynamic viscosity. Bitumen rheology examines the flow properties of bitumen, including thermoplastic, viscoelastic, and creep properties. Dynamic shear rheometers measure the viscoelastic properites of bitumens relatively simply, and are more usually torsional rheometers as described in the paper. Data about relationships between bitumen properties can be expressed by: (1) isochrones, representing a system's behaviour at constant frequency or loading time; (2) isotherms, representing it at a constant temperature; (3) master curves, involving the use of time-temperature superposition; (4) block diagrams; and (5) Cole-Cole diagrams. The paper finally discusses some properties of Superpave pavements, which are significantly better than empirical specifications but still have some disadvantages. It has a rheological glossary.

• Corporate Authors:

  INSTITUTE OF ASPHALT TECHNOLOGY

  PAPER MEWS PLACE, 290 HIGH STREET
  DORKING, SURREY  United Kingdom  RH4 1QT
• Authors:
  • READ, J M
• Publication Date: 1999

Language

• English

Media Info

• Features: References;
• Pagination: p. 67-73
• Serial:
  • THE ASPHALT YEARBOOK 1999
  • Publisher: INSTITUTE OF ASPHALT TECHNOLOGY

Subject/Index Terms

• TRT Terms: Binders; Bitumen; Bituminous mixtures; Charts; Creep; Data banks; Design; Dictionaries; Flow; Fluid dynamics; Measurement; Pavements; Properties of materials; Rheology; Thermoplastic materials; Viscoelasticity; Viscosity
• ITRD Terms: 4948: Binder; 4963: Bitumen; 4967: Bituminous mixture; 6486: Chart; 4732: Creep (mater); 8614: Database; 9011: Design (overall design); 8596: Dictionary; 5910: Durability; 5912: Elasticity; 5430: Flow (fluid); 6136: Measurement; 2955: Pavement; 3055: Pavement design; 5925: Properties; 5442: Rheology; 6138: Rheometer; 187: Specification (standard); 177: Specifications; 6722: Temperature; 7434: Thermoplastic; 5414: Time; 5935: Viscoelasticity; 5936: Viscosity
• Subject Areas: Design; Highways; Materials; Pavements;

Filing Info

• Accession Number: 00766967
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Aug 2 1999 12:00AM