BITUMEN-SAND MIXES FOR ROAD BASES

THE COST OF BITUMEN-SAND MIXES CAN BE REDUCED BY USING LESS BITUMEN THAN IS NECESSARY FOR SURFACE DURABILITY, PROVIDED THEY ARE SURFACE-DRESSED TO PROTECT THEM FROM ABRASION. TO DETERMINE WHETHER A ROAD BUILT USING THIS TECHNIQUE GIVES ADEQUATE PERFORMANCE, A SERIES OF EXPERIMENTAL MIXTURES WAS LAID ON THE MAIDUGURI-BAMA ROAD IN NORTHERN NIGERIA EARLY IN 1960. THE MIXTURES WERE MADE WITH UNHEATED SAND AND THREE CUT-BACK BITUMENS OF DIFFERENT VISCOSITY. TWO SECTIONS OF CEMENT-STABILIZED SAND WERE LAID FOR COMPARISON. THIS REPORT CONTAINS A BRIEF DESCRIPTION OF THE EXPERIMENT TOGETHER WITH THE CONCLUSIONS WHICH EMERGED FROM OBSERVATIONS DURING MIXING AND LAYING AND DURING SIX YEARS UNDER TRAFFIC. THE RESULTS SUGGEST THAT, WITH THE LIGHT TRAFFIC ON THIS TYPE OF ROAD, SAND-MIXES MADE WITH LOW BINDER CONTENTS, AND SURFACE-DRESSED SHORTLY AFTER LAYING, ARE VERY SATISFACTORY. BITUMEN CONTENTS OF 2 TO 3 PER CENT COULD BE USED WITH A VISCOUS CUT-BACK BITUMEN PROVIDED THE SAND IS WARMED TO 40-50 DEGREE C. ALTHOUGH VERY FLUID CUT-BACK BITUMENS CAN BE MIXED WITH UNHEATED SAND, IT IS UNDESIRABLE IN A DUSTY ATMOSPHERE TO LEAVE THEM UNCOMPACTED FOR THE PERIOD OF SEVERAL DAYS REQUIRED FOR THE VOLATILES TO EVAPORATE. /A/RRL/

  • Supplemental Notes:
    • Rrl Rpt Lr 239, 19 PP, 4 FIG, 2 TAB, 2 PHOT, 6 REF
  • Corporate Authors:

    MINISTRY OF TRANSPORT, LONDON (UK)

    ,    

    Road Research Laboratory /UK

    ,    
  • Authors:
    • Williams, F H
  • Publication Date: 1968-11

Subject/Index Terms

Filing Info

  • Accession Number: 00211208
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Jun 1 1970 12:00AM