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

Voids in the Mineral Aggregate. As described in Chapter 2, researchers and contractors havebeen experiencing difficulty in meeting VMA requirements, especially while designing forSuperpave mixtures. Although no direct comparison of values can be made from this research,it should be noted that it was difficult to achieve the WVDOH minimum VMA of 15 during thisresearch. This agrees with the studies performed by Coree (1999) and Kandal (1998). Both ofthese studies found that the difficulty in achieving minimum VMA requirements can beattributed to the higher compactive effort provided by the Superpave gyratory compactor.Kandal raised a question about the effectiveness of the Superpave restricted zone in relation toVMA values since only one of his designs that were passed through the restricted zone failedVMA requirements. Results of this research supported this question because the SuperpaveLow 100% LS mixture here was also passed through the restricted zone and found to have aVMA value of 15.0%, just on the line of the minimum requirement of 15.0 percent for 9.5mmmixtures.74