Date of Award
Doctor of Philosophy (PhD)
Civil and Environmental Engineering
John B. Metcalf
Airfield pavement design is a complex blend of relatively simple linear elastic theory, fatigue concepts, correlations with small and full-scale tests, and pragmatic adjustments to reflect observations of in-service pavements. The granular base and subbase have always posed the most difficult analytical problem in traditional pavement design methodologies. For this reason, the granular layers have never been treated explicitly in design as have the asphalt concrete (AC) layer and subgrade layer, which have used predictive models for cracking in the AC and rutting in the subgrade as a function of linear-elastic strain and material properties. Instead, these granular layers were carefully specified in terms of gradation, plasticity, and in-situ density to minimize deformation under traffic. However, today's designers are being asked to predict pavement performance under a variety of non-standard conditions. This is a far more complex task than simply providing safe thickness and specifications for the material. To deal with this new challenge, the design community must have material models that predict cumulative deformations under repetitive aircraft loads. With heavy loading the nonlinear response of base course materials must be considered when predicting pavement performance. The advances made in computational mechanics have created new tools of application for this type of problem, which allow for implementation of theoretically rigorous material models. In order to apply these material models, mechanical response data is required to calibrate the necessary model parameters. The parameters used to define strength, failure, and deformation properties must be defined for any material to be modeled. This dissertation describes the constitutive model requirements, laboratory tests, and analysis used in developing a response model for an unbound granular base course typical of an airfield pavement.
Smith, Donald Mark, "Response of Granular Layers in Flexible Pavements Subjected to Aircraft Loads." (2000). LSU Historical Dissertations and Theses. 7230.