Open Access Open Access  Restricted Access Subscription or Fee Access

Effects of Modifiers and Binder Properties on the Performance of Asphalt Mixtures in the Hamburg Wheel-Tracking Device Test

QUAN LV, HUSSAIN U. BAHIA, WEIDONG HUANG, NAIPENG TANG, MAO ZHENG

Abstract


The Hamburg Wheel Tracking Device (HWTD) test has been widely used in practice and reported to be successful in identifying hot mix asphalt (HMA) mixes that are prone to rutting and/or susceptible to moisture damage. This paper presents a comprehensive study aiming to offer informative references for pavement engineers to select modified asphalt materials with good moisture and rutting resistance. First, the impacts of these modifiers on the HWTD test results were investigated. Based on the degree of their improvement in the HWTD results, additives were classified into the following three grades: (1) the first grade including branched styrene–butadiene–styrene (SBS) and Gilsonite; (2) the second grade including linear SBS, high-density polyethylene, and polyphosphoric acid; and (3) the third grade including asphalt rubber (AR) and terminal blend (TB) asphalt rubber. In addition, the effects of modifier content on the Hamburg performance of the asphalt mixes were studied. It was found that higher modifier dosages do not necessarily result in the improvement of Hamburg performance. The results show that an optimal content existed for most additives, whereas a poor-performance dosage range (10.0 % - 18.0 %) existed for crumb rubber content in the AR. Finally, based on the results of the various test materials, the roles of different properties of modified asphalt binders on the Hamburg performance were also investigated. The healing, adhesive, viscosity, and elastic properties (HAVE) of modified binders were found to play different roles: the healing property of modified asphalt binder is a necessary factor; the adhesive property is a fundamental factor; the viscosity has a maximum limitation (3.5 Pa∙s at 135°C); and the elastic property due to the modification is the determining factor in achieving good Hamburg performance of modified asphalt mixtures.

Keywords


Hamburg Wheel-Tracking Device test; asphalt mixture; modifiers; rutting; moisture sensitivity.Text


DOI
10.12783/aapt2018/33803

Full Text:

PDF

Refbacks

  • There are currently no refbacks.