Field Investigation and Accelerated Pavement Testing of Inverted Pavement System

Inverted pavement is an unconventional type of flexible pavement structure. In this pavement structure, an unbound aggregate base (UAB) with a low initial modulus is sandwiched (layered) between two stiffer layers, a thinner asphalt concrete layer (AC) and a cement-treated aggregate base layer (CTB). This type of pavement structure has been a potential alternative to the conventional flexible pavement structure due to its cost-efficient usage of asphalt, comparable performance, and durability based on past studies. However, field investigations of inverted pavement have not been widely conducted and are very limited in the USA. The objective of this study is to present a comprehensive investigation of inverted pavement systems including field and laboratory works. The effect of the nonlinear stress-dependent property of unbound aggregates on both the inverted and conventional flexible pavement structures was first investigated. Second, through field investigation of a Vulcan Materials Company Quarry entrance road, a comparison study between the inverted and conventional pavements was conducted under the same traffic level and environmental conditions. Nondestructive pavement testing – falling weight deflectometer (FWD) was applied to evaluate the structural conditions of the inverted pavement, contributing to the effective maintenance and preservation of pavements. Finally, the accelerated pavement testing (APT) method was used to evaluate the rutting performance of full-scale inverted pavement constructed on the University of Tennessee (UT) campus. Based on the results of the comprehensive investigation of field construction, numerical simulations, and full-scale laboratory tests using APT, the inverted pavement structure can be regarded as a viable alternative to the conventional flexible pavement.