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

555.2.4 Specimen TestingSuperpave mix design relies solely volumetric properties of the mix. No physical test is currentlyrequired. However, the APA test developed by the Georgia DOT is gaining popularity withvarious state agencies and researchers.Testing was conducted on all specimens along the range of asphalt contents tested and valuesinputted into an Excel spreadsheet programmed specifically for Superpave. This program thencalculated the air voids, VMA and VFA from the measured bulk weights of each specimen andgraphs made of each of these properties versus asphalt content.From the graphs developed by the spreadsheet, the asphalt content corresponding with 4% airvoids was determined. This asphalt content was the design asphalt content. VMA and VFAvalues of the mix were determined by finding the values for each that corresponded with thedesign asphalt content. Volumetric values were then checked for compliance with requiredvalues set forth by Superpave.Once the optimum asphalt content has been found, a set of N max specimens were prepared. Ifthe sample met Superpave specifications, then the mix was determined to be an acceptable mix.5.2.5 Mix Design ResultsResults of the Superpave designs were calculated using an Excel spreadsheet. Tables and graphscontaining the full mix design data for each Superpave mix design are presented in Appendix Cand are summarized in Table 5.4.All properties were within WVDOH specifications except for those indicated by the heavy boxes.As indicated in Chapter 4 the fine aggregate used did not meet the specifications for heavytraffic volume design. As expected the 100% limestone mixes exhibited a higher FAA value thanthat of the mixes containing 13% natural sand. Another source for sand was not sought to raisethis value above the minimum of 45 needed to meet requirements due to the need to keep thesand content consistent throughout the research. This allowed for accurate comparisons to bemade without the added complication of considering variations in material properties.