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RUT MIX CHALLENGE. GAUTRANS RPF NOVEMBER 2006. RUT MIX CHALLENGE. The need arose from increased occurrence of premature failures As a result Client bodies want to move away from asphalt to concrete Better solution would be a properly designed asphalt that will be: Rut resistant
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RUT MIX CHALLENGE GAUTRANS RPF NOVEMBER 2006
RUT MIX CHALLENGE • The need arose from increased occurrence of premature failures • As a result Client bodies want to move away from asphalt to concrete • Better solution would be a properly designed asphalt that will be: • Rut resistant • Durable at low and high temperatures • “User Friendly” (Manufacturing & Placing)
RUT MIX CHALLENGE • Role players in asphalt industry to develop 2 asphalt mix designs namely: • Rut resistant intersection mix • Every day highway mix • Subsequently high modules asphalt included • Shell with low pen binder (French Technology) • Sasobit with 40/50 or Sasoflex (German & French Technology) These mixes will then be paved on a freeway in Pretoria and tested for rutting, fatigue etc.
RUT MIX CHALLENGE • Rules for mix design: • No modified binders (Rut mix & Highway mix) • Any grading (Not limited to Colto Spec.) • Mixes to be verified prior to paving of trials in Pretoria • Reference mix to be paved and tested prior to trials being paved
RUT MIX CHALLENGE WEST RAND
RUT MIX CHALLENGE Mix design process • First plant trials completed • Intersection mix is promising (Performance testing indicates good rut resistance) • Paving trial planned on R25 • Freeway mix needs refining • Further plant trials planned
RUT MIX CHALLENGE EAST RAND
RUT MIX CHALLENGE • Verification with Performance Properties
RUT MIX CHALLENGE AKASIA ROAD SURFACING
RUT MIX CHALLENGE Akasia Road Surfacing - Mix design process • Design in process • Change of aggregate source (From Rooiberg to Granite from Buffalo quarry Naboomspruit) • Mix type not finalized
RUT MIX CHALLENGE BLACK TOP NICO WILCOCKS
RUT MIX CHALLENGE Mix design process • TRH8 Coarse • Chrome Slag from Witbank • High PSV • Rough surface texture • Good adhesion • Varying surface area • No swell problems • Mix used successfully on N4 at Tollgate bypass NICO WILCOCKS
RUT MIX CHALLENGE HIGH MODULUS ASPHALT (HiMA)
RUT MIX CHALLENGE High Modulus Asphalt (HiMA) Mix design process Sasobit • Soillab busy with mix designs similar to Hamburg International Airport (40/50 Bitumen + 3% Sasobit) Shell • Aggregate and bitumen samples sent to Shell Global Solutions France (Low pen bitumen)
ACHIEVING VOLUMETRICS IN ASPHALT BAILEY METH0D
Bailey Method • What is voids and VMA? Volume Voids (3% - 6%) VMA Volume Binder (10% - 17%) Volume Aggregate (83% – 90%)