UTW behavior on asphalt pavements tested with HWLS

Abstract

The objective of this research is to evaluate how the physical properties and thickness of asphalt pavements influence behaviors of ultra thin whitetopping (UTW). The results of the three-dimensional finite-element method reveal that properties of asphalt and concrete layers, bonding between the two layers, and temperature strongly affect the distress of UTW. Based on results of FEM analysis, a wheel tracking device called the "heart wheel load simulator (HWLS)" was developed and used to perform an experiment to observe behavior variation in accordance with asphalt and concrete layer thicknesses as well as temperature. The results of HWLS simulation show that the effect of temperature is not significant and the increase of the tensile strain with the increase of a load is relatively small for a 100 mm concrete layer, as compared to a 50 mm concrete layer. In addition, for a 50 mm concrete layer with a less than 150 mm asphalt layer, the increased ratio of the tensile strain at the bottom of the concrete slab is significantly higher. Therefore, this research recommends that an at least 150 mm asphalt layer after milling be required in order to apply UTW safely.