Effect of Binder Type, Mastic, and Aggregate Type on the Low-Temperature Characteristics of Modified Hot Mix Asphalt

摘要

The purpose of this study was to evaluate the effect of binder type, mastic, and aggregate type on the low-temperature cracking characteristics of asphalt mixtures. Six different performance grade (PG) binders were utilized for this study: PG64-28, PG64-28 with poly phosphoric acid, PG64-34 SBS, PG76-22 SBS, a terminal blend asphalt rubber, and PG64-28 with 2% latex. Each binder was tested to determine its low-temperature cracking resistance using the asphalt binder cracking device (ABCD) and the Superpave tests. A Superpave 9.5 mm mixture was designed using each of the six binders for this study and two sources of aggregates (crushed stone and gravel). Each mixture was then tested for low-temperature cracking resistance using the asphalt concrete cracking device (ACCD). Mastics corresponding to each mixture were tested for low-temperature cracking resistance using the ABCD. Analysis of the results showed that the AASHTO critical cracking temperature had a strong correlation with the ABCD binder and mastics results, but did not correlate well with the mixture tests. Mastic testing generally did not correlate well with the mixture test results. ABCD and ACCD tests results indicated that they were sensitive to binder type, aging time, and aggregate types.