Precoated chippings may become non-adhesive due to hardening or "coking" of the binder if the chippings are stored at high temperatures for more than a few hours. The development of two tests for assessing the adhesiveness of coated chippings is described. In the hot-sand test chippings are surrounded by sand at 130 deg C and the weight of adhering sand after a standardised abrasion procedure is determined; it is recommended that this should not be less than 40 g/kg of chippings. Poor-quality chippings within a sample are also indicated. In the solvent test chippings are washed in petroleum ether, 120-160 deg C boiling range, and then individually examined for insoluble bitumen indicating "coking"; results similar to the hot-sand test can be obtained. The repeatability of the mass of sand retained in the hot-sand test is estimated as about 8 g/kg and the reproducibility as about 12 g/kg. In a road experiment coated chippings having less than 40 g/kg retained sand showed significant losses. In two further road experiments it has been shown that there is no significant deterioration in quality during normal handling from the stockpile to the road. The tests are now included in the 5th edition of the DOE specification for road and bridge works.(a)

  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Authors:
    • DAINES, M E
  • Publication Date: 1977

Media Info

  • Features: References; Tables;
  • Pagination: 15 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00165589
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Report No. 313
  • Files: TRIS, ATRI
  • Created Date: Feb 16 1978 12:00AM