A METHOD FOR CALCULATING FATIGUE DAMAGE OF FLEXIBLE ROAD PAVEMENTS --BITUMEN, FLEXIBLE AND DURABLE. 3RD EUROBITUME SYMPOSIUM 1985, THE HAGUE, NETHERLANDS, SEPTEMBER 11-13, 1985

Fatigue damage of flexible road pavements is usually calculated by means of miner's law. However, this law does not take into account the application order of load cycles with different amplitude. It is evident that a material subject to load cycles with different amplitude endures fatigue better if stressed with load cycles with lower amplitude first and then higher amplitude, rather than the contrary. In order to find a new method for calculating fatigue damage the studies of fatigue phenomena in metals have been resorted to, though carefully considering the actual possibility of using the results obtained also in roads. Starting from the consideration that a material does not exhibit any fatigue damage if subject to cycles with a maximum stress below a certain value, we arrived at the conclusion that the curves representing the same fatigue damage in a semilogarithmic diagram (stresses-log of the number of load repetitions) are straight lines meeting at the same point. It is therefore possible to define fatigue damage as the ratio of the tangents of the isodamage line to the tangent of the failure line. By means of a suitable mathematical approach, it was possible to represent the number of load cycles with a certain amplitude producing the same fatigue damage produced by a pre-established number of cycles with different amplitude. This method can be used in the road sector as shown by the experiments carried out on specimens of bituminous mixture. In fact, there exists a point at which the failure lines of different specimens converge, each having a specific complex modulus. At this point the passage from the failure lines for bituminous mixtures to the isodamage lines is automatic. The application of this method in fatigue verification of flexible superstructures enables US to follow the actual behaviour of the material in a more realistic way, since the order of application of the loads to the pavement is taken into account, though using the modified verstraeten fatigue curve.(a) for the covering abstract of the symposium see IRRD 815173.

• Corporate Authors:

  EUROBITUME

  BD EMILE BOCKSTAEL 351
  Bruxelles, ZZ Belgique   
• Authors:
  • Bucchi, A
  • Negro, F
• Publication Date: 1985

Language

• Undetermined

Media Info

• Pagination: p. 272-7
• Serial:
  • Publication of: EUROBITUME
  • Publisher: EUROBITUME

Subject/Index Terms

• TRT Terms: Amplitude (Physics); Bituminous mixtures; Conferences; Failure; Fatigue (Mechanics); Flexible pavements; Loads; Loss and damage; Mathematical models; Repeated loads; Samples
• Subject Areas: Data and Information Technology; Highways;

Filing Info

• Accession Number: 00482103
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Apr 30 1989 12:00AM