Abstract
Ultra-thin bonded bituminous surface (UBBS) is a surface treatment that consists of a thin, gap-graded hot-mix asphalt (HMA) layer applied over a thick polymer-modified emulsion membrane. The aggregates and asphalt used in UBBS are of very high quality. The objective of this study is to evaluate whether reclaimed asphalt pavement (RAP) materials from existing UBBS layers can be used in chip seal and Superpave mixtures. UBBS RAP were studied with two different polymer-modified emulsions to assess their performance as precoated aggregates in chip seal using ASTM D7000-04 sweep test. Three different Superpave mix designs were developed for both 12.5-mm and 9.5-mm nominal maximum aggregate sizes (NMAS) using three different percentages (0 %, 10 %, and 20 %) of UBBS RAP materials. The designed Superpave mixes were then tested using the Hamburg wheel tracking device (HWTD) and the modified Lottman tests. Sweep test results showed that UBBS millings did not improve chip retention. Superpave mix design data indicated volumetric properties of Superpave mixes with UBBS millings met all requirements. HWTD and modified Lottman test results indicated all designed mixes performed better with the addition of UBBS RAP materials.
