An appraisal of the state of compaction of dense coated macadam bases and base-courses being achieved in current British construction practice reveals a considerable range of compaction levels and that the initial variation of density across the laid width persists after many years of intense commercial traffic. The effects of material composition, compactive effort, roller speed, rolling temperatures and stiffness of the working platform are analysed. An examination of the rolling procedures indicated that there is scope for increasing the level of compaction in the critical wheel path zone. Modified rolling procedures have been successfully used to improve compaction in the wheel paths. A brief summary is given of British experience with thick lift construction including results from a full-scale road experiment. Good compaction was achieved at the expense of some loss of riding quality when the base and basecourse were combined in one lift. The relation between performance of dense coated macadams and their compacted state has been studied in an associated programme of pilot scale and laboratory testing. Results show that worthwhile performance benefits are obtained if compaction in the wheel paths is increased to the peak values now being obtained in the centre of the laid widths. The suitability of cheaper base and basecourse materials of binder contents lower than those currently used in the United Kingdom is also being studied and preliminary results showing considerable promise are presented.(a) /TRRL/

  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Authors:
    • Lister, N W
    • Powell, W D
  • Publication Date: 1977

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 38 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00156449
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: TRRL SR260
  • Files: TRIS, ATRI
  • Created Date: Oct 13 1977 12:00AM