The National Institute for Road Research has developed a brake-force trailer which has been used to measure the skid-resistance of asphaltic concrete, gap-graded asphalt with and without precoated chippings, open-graded asphalt, surface treatments and surfacings with slurry over a layer of stone. The results of measurements on a sample of these surfacings are presented and the influence of surface texture depth, state of polish of the stone and the effect of a fatty surface are discussed. The results at 100 km/h depended mainly on the surface texture depth, irrespective of the type of surfacing. The correlation established between the brake-force coefficient at 25 km/h and the pendulum value indicates that the former is also a measure of the harshness (or state of polish) of the stone. A fatty surface reduced the skid-resistance at all speeds, and gave a particularly low value at 100 km/h. The noise measurements indicated that the type of surfacing had little effect on the noise inside a vehicle at a speed of 130 km/h, but had an effect at lower speeds. With regard to the effect of noise on the environment, the open-graded asphalt generated significantly less noise than, for example, a coarse textured surface treatment. Open-graded asphalt, which has a high skid-resistance by virtue of its ability to drain water through the voids in the layer, therefore holds promise of providing good skid-resistance together with low noise generation, which would be an important requirement for urban freeways. (a). This paper was presented at the 2nd conference on asphalt pavements for Southern Africa, Durban, 29th July-2nd August, 1974. See also IRRD Abstracts Nos. 216602-216619. /TRRL/

  • Corporate Authors:

    Council for Scientific & Industrial Res S Africa

    P.O. Box 395
    Pretoria,   South Africa 
  • Authors:
    • Visser, A T
    • Walker, R N
  • Publication Date: 0

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 12 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00131452
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: RR179 R&D Rept.
  • Files: ITRD, TRIS
  • Created Date: May 14 1976 12:00AM