Indirect tensile strength method for defining a proper practice of asphalt mixtures design

Abstract

This paper shows the results of a laboratory investigation of indirect tensile strength test effects on bituminous mixtures characterization. In particular, the research focusses, in the first analysis, on the procedure of Marshall mix design, where 4 different mixtures of hot mix asphalt (HMA) were prepared at different bitumen contents between 3.5% and 4.25% by total aggregate weight at 0.25% increments. In the second phase, bituminous specimens made-up by gyratory compactor in compliance with Marshall optimization were tested to evaluate their indirect tensile strength. It was ascertained how the air voids percentage and indirect tensile strength can change by varying the number of revolutions during gyratory compaction and the height of specimens. A one-way ANOVA test was finally carried out to verify whether statistically significant differences exist in terms of mechanical properties when the number of revolutions and the specimen size change. This research may help to provide administrations with fast laboratory procedures to use in situ for all activities related to acceptance of mixtures.