The Transport and Road Research Laboratory (TRRL) are engaged in a programme of research to develop a system of road pavement design that is less empirical than current methods and is more closely related to the structural value of the component materials. The investigation of the fatigue resistance of rolled asphalts, reported in this thesis, is a part of that programme. Existing knowledge on the fatigue properties of bituminous materials is reviewed, and the method of production of test specimens, the development of the necessary testing system and the experimental procedures used by the author are described. Details are given of experiments designed to examine the importance of some of the differences between laboratory tests and the service environment of a road pavement; in particular the effects of various waveform parameters, including rest periods, were investigated. Also described is a series of tests which measured the residual laboratory fatigue resistance of materials taken from sections of a full scale road experiment, for comparison with insitu performance. The author observed that, while variations in the shape of the applied waveform produced fairly small changes in fatigue endurance, the inclusion of rest periods between individual load pulses increased fatigue lives manyfold. It is suggested that there are at least two forms of damage mechanism: 1) The predominant mechanism of damage in the early stages of the fatigue process is probably a physico-chemical change in the binder, caused or accelerated by the repeated application of loads, and this change recovered to a considerable degree during rest periods between loads. 2) In the latter stages of the fatigue process cracking became the predominant damage mechanism. It is suggested that during crack propagation, damage can usefully be considered to occur in two stages; the first, which is recoverable, being the development of localised conditions conducive to cracking, the second being crack propagation. The author also discusses, briefly, some possible effects of fatigue weakening on the pavement structure. /TRRL/

  • Corporate Authors:

    Council for National Academic Awards

    344-354 Gray's Inn Road
    London,   England 
  • Authors:
  • Publication Date: 1975-1

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 289 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00132639
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Monograph
  • Files: ITRD, TRIS
  • Created Date: Nov 9 1977 12:00AM