Date Approved

7-12-2019

Embargo Period

8-12-2019

Document Type

Dissertation

Degree Name

PhD Engineering

Department

Civil and Environmental Engineering

College

Henry M. Rowan College of Engineering

Advisor

Mehta, Yusef

Committee Member 1

Cleary, Douglas

Committee Member 2

Lomboy, Gilson

Keywords

Finite-Element Modeling, Geogrid Reinforcement, Hot-Mix Asphalt, Life-Cycle Cost Analysis, Performance Testing

Subject(s)

Runways (Aeronautics)--Maintenance and repair; Geogrids; Pavements, Asphalt

Disciplines

Civil and Environmental Engineering | Geotechnical Engineering

Abstract

The objective of this study was to evaluate the fatigue cracking performance of geogrid-reinforced Hot-Mix Asphalt (HMA) for use in airfield runways. An airfield HMA mixture with four different geogrid types were selected for this study. The geogrids varied in tensile strength, coating type, opening size, thickness, and fiber material. Several different laboratory performance tests were conducted (Dynamic Complex Modulus, DCM, Overlay Test, OT, and Indirect Tensile Strength, ITS) and the fatigue and/or cracking performance was evaluated. Additionally, different approaches were adopted or developed for the modeling of geogrids in HMA using Finite Element Modeling (FEM). Finally, a Life-Cycle Cost Analysis (LCCA) was conducted to determine if the additional investment of using geogrids in HMA is a cost-effective strategy over the pavement service life. Overall, this study discovered a significant increase in the fatigue cracking performance when reinforcing HMA airfield mixtures with geogrids. Additionally, the geogrids exhibited crack deterring characteristics that slowed down crack propagation in the HMA mixture, especially when embedded below the neutral axis. Furthermore, a unique approach of FEA was developed to evaluate impact of geogrid-reinforced HMA mixtures under different loading conditions and configurations within a pavement system. Finally, geogrids proved to be a cost-effective strategy when the reinforcement is embedded below the mid-depth of the HMA layer.

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