Tom Scullion

Bio: Tom Scullion is an academic researcher from Texas A&M Transportation Institute. The author has contributed to research in topics: Falling weight deflectometer & Pavement engineering. The author has an hindex of 29, co-authored 275 publications receiving 4249 citations. Previous affiliations of Tom Scullion include Texas A&M University System.

Verification and modeling of three-stage permanent deformation behavior of asphalt mixes

Abstract: In laboratory testing of asphalt mixtures, the relationship between the number of load repetitions and permanent deformation has been found to include three distinct stages, namely the primary, secondary and tertiary stages. Similar permanent deformation behavior has also been observed in the field accelerated pavement testing data. It is argued that the three-stage permanent deformation behavior is a basic material property and to comprehensively model asphalt layer behavior, it is necessary to develop a model that accurately characterizes this behavior. In this paper, each of the well-known models critically reviewed appears that they are limited to characterizing only the primary stage. Therefore, a new three-stage model is proposed to describe all three stages. Moreover, an algorithm is established to determine the model parameters from typical laboratory data. The algorithm can also be used to identify the transition point between stages, such as flow number. The proposed model and algorithm are demonstrated through laboratory test results. The analysis results match the field performance.

Development of an IDEAL Cracking Test for Asphalt Mix Design and QC/QA

Abstract: The focus in recent years has been to make asphalt mixes more affordable, and this has led to the increased use of recycled materials and binder modifications. Consequently, one often-heard complai...

Using Suction and Dielectric Measurements as Performance Indicators for Aggregate Base Materials

Abstract: A simple laboratory test for evaluating unstabilized granular base material is introduced. The test consists of monitoring the capillary rise of moisture within a 300-mm-high cylinder of compacted aggregate. The moisture conditions at the aggregate surface are monitored with a dielectric probe. A graph of surface dielectric versus time is used as the basis for performance classification. The poorest-performing materials are those that rapidly reach saturation and exhibit high surface dielectric values. The dielectric is a measure of the “free” or unbound water within the aggregate sample. It is not a simple measure of the moisture content of the material but an assessment of the state of bonding of the water within the fine aggregates. It is this unbound water that is thought to be directly related to the strength of the material and to its ability to withstand repeated freeze-thaw cycling. This test was developed by the Finnish National Road Administration and successfully used to investigate a major fle...