THE DEGRADATION OF ROADBASE AGGREGATES - RESULTS FROM LABORATORY TESTS

NEDBRYTNINGSBENAEGENHET HOS BAERLAGERGRUS--RESULTAT FRAAN LABORATORIEFOERSOEK

Results from laboratory test methods were compared with the degradation that was found by sampling on road projects. Attempts were also made to study degradation by construction traffic on a test track. In the laboratory tests the roadbase aggregates were exposed to impact compaction, closely corresponding to AASHTO T 180, and wearing action in a planetary-type mixer. The tests were made at approximately optimum water content. Insufficient fines are formed by the impact compaction tests compared with road conditions. In comparison the fines are less plastic than in the road samples. Wearing action for 10 minutes in the mixer produced approximately as many fines as found in the road and the plasticity of the fines corresponds better with the road samples. The degradation of coarse particles is small. The wet degradation test in a planetary-type mixer produces the most relevant results as the tendency to form fines is one of the most important quality criteria for roadbase aggregates. The test must be made primarily on certain problematical aggregates. For avoiding unnecessary testing, an aggregate classification is suggested and aggregate properties of the different classes are discussed. /TRRL/

Language

  • Swedish

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 180 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00179895
  • Record Type: Publication
  • Source Agency: Swedish National Road and Traffic Research Institute
  • Report/Paper Numbers: VTI Report No. 140 Monograph
  • Files: ITRD, TRIS
  • Created Date: Sep 27 1978 12:00AM