Impact of the Interlayer Scabbing on Asphalt Pavement Performance

Abstract

A full-scale experiment was conducted at the Florida Department of Transportation’s accelerated pavement testing (APT) facility to identify factors affecting the occurrence of interlayer scabbing and the impact of scabbing on pavement performances. Two experimental parameters—interlayer bonding condition of existing asphalt layers and milling thickness—were considered for the first objective. For the second objective, core specimens were obtained after the hot mix asphalt overlay on sections where scabbing was present and not present to compare their interlayer bonding strengths. In addition, APT was utilized to assess the rutting and cracking performance of the test sections. Test results indicated that the occurrence of scabbing is highly dependent on the interlayer bonding condition of the existing asphalt layers and milling depths. Once scabs form after milling, the scabs result in a weak or variable bond with the new overlay. Also, the accelerated loading using heavy vehicle simulator generated approximately 30% greater rut-depth and longitudinal cracks along the edge of the wheel path on the test sections with interlayer scabbing. In consideration of the reduced performance of the test sections with interlayer scabbing, the authors suggest preventing or removing the scabbing before the asphalt overlay.

Investigation on One-Component Waterborne Epoxy Emulsified Asphalt (OWEEA) Used as Bonding Material

“…With the development of pavement materials and preventive maintenance techniques [1][2][3][4], the application of ultra-thin overlays and functional pavers has become increasingly widespread [5][6][7]. However, it is difficult to ensure the interlayer bonding performance due to differences in material properties and relatively weakened mechanical compatibility between the upper and lower cladding layers, as well as surface contamination of the lower cladding layer caused by milling [8,9]. The resulting interlayer disease problem has become a key factor restricting development [10], so the bonding layer materials must meet higher requirements [11][12][13].…”

Evaluation of the Effect of Interlayer Bonding Condition on the Deterioration of Asphalt Pavement

“…Hachiya and Sato ( 5 ) compared the damage conditions of pavement with different construction intervals of two asphalt layers, examined the effect of tack coat conditions, and proposed a new laboratory test to ensure interlayer bonding. Kwon et al ( 6 ) conducted an accelerated loading test using Florida Department of Transportation’s (FDOT’s) heavy vehicle simulator on pavement with various interlayer bonding conditions, and showed that pavement cracks occur early when the interlayer bonding is not present. However, these studies did not actually measure the strain generated inside the pavement, and the consistency between models or laboratory tests and the actual pavement was not confirmed.…”