01476241

Component

Chip seals generally deteriorate as a result of asphalt oxidation, wear and polishing of aggregate, bleeding, and raveling (loss of aggregates). In this study, two major environmental effects on chip seal performance, freeze-thaw and asphalt aging were investigated based on laboratory tests and field distress survey. For freeze-thaw evaluation, laboratory chip seal samples were prepared for 18 combinations (6 aggregates X 3 asphaltic materials). A simple freeze-thaw protocol was developed. It was observed that freeze-thaw loss is much higher than post freeze-thaw sweep test and control (dry) sweep test. Evaluation of freeze-thaw effect on aggregate types reveals that both the precoated and uncoated expanded shale lightweight performs comparatively very well against freeze-thaw plus sweep test. Evaluation of freeze-thaw effect on asphaltic materials types reveals that CRS-2P performs better than PAC-15 and AC20-5TR. For aging evaluation, asphaltic materials were extracted from 15 (5 aggregates X 3 asphaltic materials) field test sections and increase in stiffness due to aging were determined using a dynamic shear rheometer. For each of the five aggregates, CRS-2P shows the lowest G*/sinä indicating minimum field aging susceptibility among the three asphaltic materials. For each of the aggregates, AC20-5TR shows slightly higher G*/sinä than PAC-15 indicating maximum field aging susceptibility among the three asphaltic materials used in this study. It is evident from this study that precoating of aggregates increased the aging indices. For the field evaluation, fifteen chip seal test sections were prepared with three asphaltic materials and five aggregates in a 9-acre parking lot. Overall field distress ratings of the CRS-2P sections are better than those of PAC-15 sections and overall distress ratings of PAC-15 (sum of distress ratings of all the PAC-15 sections) sections are better than overall distress ratings of AC20-5TR sections which closely reflect the observations in freeze-thaw evaluation and asphalt aging evaluation.

This paper was sponsored by TRB committee AHD20 Pavement Maintenance.

01470560

13-5094

English

23p

2013

Transportation Research Board 92nd Annual Meeting

Digital/other

Figures; Photos; References; Tables

Aging (Materials); Asphalt pavements; Chip seals; Deterioration; Environmental impacts; Freeze thaw tests; Laboratory tests; Pavement distress

Highways; Maintenance and Preservation; Pavements; I60: Maintenance

Transportation Research Board Annual Meeting 2013 Paper #13-5094

TRIS, TRB, ATRI

Feb 5 2013 12:58PM