01626231

Component

The durability of asphalt concrete and its resistance to moisture damage significantly affect pavement service life. Preventing moisture damage and stripping is especially required when siliceous aggregates are used. Typically, anti-stripping agents are used that mainly change aggregates’ affinity for water by changing their zeta potential (negative surface charge can promote bitumen adsorption), or binders are modified to promote interface bonding between stone particles and bitumen. However, applications of anti-stripping agents or adhesion promoters are usually costly and in some cases may even change some performance characteristics of the pavement. Accordingly, in this paper, the authors examined the merits of applying natural bitumen (gilsonite) as an anti-stripping additive. Gilsonite is a low-priced mineral material with chemical composition near that of petroleum-based asphalt. The compatibility of gilsonite and bitumen has been reported in prior research. Due to the high durability properties observed in gilsonite-modified asphalt, this paper hypothesizes that introducing gilsonite to paving mixtures containing siliceous minerals will enhance the mixtures’ overall moisture resistance. Therefore, in this study, bitumen was modified with 5 and 10 percent gilsonite in siliceous mixtures. Chemical properties and functional groups of bitumen in the presence of gilsonite were examined using Fourier transform infrared spectroscopy. In addition, the indirect tensile strength test was conducted on each gilsonite-modified specimen both in dry status and after freeze-thaw conditioning. Gilsonite-modified specimens showed improved resistance to moisture. However, the improvement effect was not significantly different between 5 and 10 percent gilsonite dosage.

This paper was sponsored by TRB committee AFK40 Standing Committee on Surface Requirements of Asphalt Mixtures.

01618707

17-05663

English

0000-0003-4829-9681

16p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Antistrip additives; Asphalt concrete; Asphalt concrete pavements; Durability; Fourier transforms; Infrared spectroscopy; Stripping (Pavements)

Gilsonite; Indirect tensile strength; Moisture resistance; Moisture sensitivity; Siliceous aggregates

Highways; Materials; Pavements

Transportation Research Board Annual Meeting 2017 Paper #17-05663

TRIS, TRB, ATRI

Dec 8 2016 12:16PM