Comparison of 9.5 mm SuperPave and Marshall Wearing I Mixes in ...

27Coal and other lightweight deleterious materials,Friable particles,Percent wear, andSoundness.The WVDOH Marshall aggregate specifications that are comparable to the Superpave consensusproperties are:Thin or elongated particles, andCrushed particles.Although both Marshall and Superpave have specifications for these parameters, the testmethod and criteria for the thin or elongated particles are different. The specification criteriafor crushed particles (Marshall) or fractured faces (Superpave) are different. The WVDOHMarshall specification for Wearing I mixes requires a minimum of 80% particles with twofractured faces. The Superpave fractured face specification for 9.5mm mixes is on both one andmore than one fractured face and the limits vary by design traffic level and depth of the mixfrom the pavement surface.The Superpave method requires two consensus aggregate properties that are not considered inthe Marshall method:Fine aggregate angularity, andSand equivalency.The WVDOH mix design criteria for both the Marshall and Superpave methods include VMA,VFA, VTM, and D/B as shown in Table 2.6. The VMA values are equal for the Superpave method.The VFA criteria are very similar. The Marshall requirement for VTM show a range of 3 to 5%and the Superpave requirements are for exactly 4.0%. However, the Marshall method calls fordesigning for the median value of this range, 4%. Both the Marshall and Superpave methodshave restrictions on the dust to binder ratio. However, the Marshall method uses the totalbinder content in the denominator whereas Superpave uses the effective binder content.