The permanent deformation and fretting (loss of mortar and stones) has been investigated under semi-practical conditions in a circular test track. In this track 0.80 m long and 600 mm thick asphalt sections were laid on top of a 20 cm thick cement-stabilized sand base. The composition of the permeable asphaltic concrete was: 85% gravel and 2-12 mm, 10.5% w crushed sand, 4.5found w filler, 4.2 pha binder, and 18% (approx) voids content. A dense coarse asphaltic concrete was included for comparison. Apart from the use of a conventional 80/100 pen bitumen with both mix types an additional step was applied in which the sand and stones were precoated with about 1.5 pha of a special bitumen to obtain improved adhesion. Details of the study are outlined. It was found that the permanent deformation of blank porous asphalt mix is only slightly higher than that of the dense mix. The resistance to permanent deformation is slightly increased by using a doped bitumen and further increased by using precoated aggregate. The best results are obtained by combining the precoating with the use of a premium binder. As the number of wheel passages increased, loss of mortar and stones was observed in various sections starting from the outer side of the wheel track. All studies show that the use of modified binders, combined with precoated aggregate, will increase the durability of porous mixes.

Media Info

  • Features: Figures;
  • Pagination: p. 196-199

Subject/Index Terms

Filing Info

  • Accession Number: 00163677
  • Record Type: Publication
  • Report/Paper Numbers: S.C.W. Record 2 Proceeding
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM