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Dr. Masad research focuses on constitutive modeling of asphalt mixtures, asphalt pavements performance, transport in porous media, granular mechanics, microstructure characterization of materials, and image analysis techniques.  A complete list of his research publications and research projects can be found in his resume.  He has active research groups and programs in the United States and in the State of Qatar.  Examples of research programs that he is involved in are highlighted herein.

 Asphalt Research Consortium (ARC)

The Asphalt Research Consortium is a group of five organizations bringing an extraordinary depth and range of asphalt experience to bear on significant needs of the asphalt community. Under a cooperative agreement with the FHWA, they have initiated a new program in 2007 to:

It is expected that this unprecedented team effort will accelerate progress in addressing key asphalt pavement performance issues.

Finite Element Simulation of Asphalt Pavement Performance Using Nonlinear Models

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Research on Infrastructure Materials in the State of Qatar

 The following research projects are being conducted in the State of Qatar with the objective of improving the performance of infrastructure materials and systems.

 This project aims at the development of comprehensive system for selection of asphalt road materials and prediction of the performance of asphalt pavements in the State of Qatar.  This system will be developed based on fundamental physio-chemical properties, nondestructive microstructure imaging techniques and advanced constitutive models for predicting performance.  The results of this study will be a significant improvement over the current empirical material characterization and methods.  It will enhance the sustainability of road systems in Qatar and reduce construction cost. 

                 Dynamic Mechanical Characterization of Asphalt Mixtures

 Asphalt pavement is a complex composite that comprises mineral aggregates and a binder which is a by-product from the distillation of crude oil. Its mechanical properties vary significantly depending on the mineral content, the proportions, size, and distribution of aggregates, and the thermophysical and mechanical properties of the constituent materials. Sophisticated design and characterization tools are needed if long-lasting roads capable of supporting the future transportation infrastructure are to be adequately constructed in the State of Qatar. Accordingly, this project involves the development of computational models for simulating asphalt pavement performance under realistic loading conditions. The asphalt pavement behavior will be represented by advanced constitutive models that span over micro, meso, and macro length scales. The computational models will include the application of realistic loading configurations based on experimental measurements of tire-pavement contact stresses and interactions. The modelís parameters will be determined through extensive laboratory testing of asphaltic materials used in Qatar. The developed model will be validated with field data. A feature of our work is the use of nondestructive imaging techniques to describe the microscopic features of asphalt concrete under various loads and external conditions.

Three-Dimensional Aggregate Structure in a Section of an Asphalt Mixture

Digitization of Microstructure of Asphalt Mixture for Finite Element Simulation of  Fracture

 

Damage in Asphalt Mixtures Using the Pavement Nonlinear Damage Analysis (PaNDA) Model.

 

The performance of asphalt pavements depends crucially on the strength and stability of the supporting soil layer, referred to as the subgrade.  A pavement subgrade failure can be catastrophic: extremely hazardous to traffic and extremely expensive to rectify.  This project will evaluate the technical aspects and commercial potential of a novel method which stabilizes subgrade soil by polymerization.   The project involves evaluation of chemical and mechanical properties of polymer-stabilized soils and performance evaluation of stabilized asphalt pavements.

 

 

X-ray Computed Tomography System for Capturing Material Microstructure

Scanning Electron Microscope Analysis of Soils

  • Monitoring and Performance Evaluation of Thiopave Asphalt Modifier Sections in Ras Laffan, Funding Source, Shell Company in Qatar

     

This project focuses on field monitoring of the performance of the trial road stretch that is located in Ras Laffan Industrial City (RLIC), Qatar.  This road includes a section that was constructed usingShell Thiopave asphalt modifier followed and a conventional asphalt mixture.  The project is conducted with Shell Sulphur Solutions, which has carried out laboratory characterization of the Shell Thiopave-modified and conventional mixtures used in the field trial section.

 




Shell Thiopave Asphalt Mix Laydown in RLIC on October 30th 2007.

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International Collaboration on Surface Energy, Adhesion and Micro-Structural Characterization

This program is funded by the Engineering and Physical Sciences Research Council (EPSRC) in the United Kingdom . It is a people-based activity which will add value and increase research outputs in the area of paving materials by providing a dynamic environment for the exchange of ideas and research philosophies. The program is targeted at studying the fundamental properties of pavement materials based on the principles of material science, micro-structural characterization, and mechanics. The focus of the proposed program is on including expertise from disciplines outside the general area of pavement engineering as well as strengthening international collaboration.   The research partners in this program are:

  • Nottingham Transportation Engineering Centre, University of Nottingham

  • Materials Group, Zachry Department of Civil Engineering and Texas Transportation Institute, Texas A&M University

  • Adhesion and Adhesives Group, Department of Mechanical Engineering, Imperial College

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Mathematical Models to Scientifically Explain the Compaction of Hot Mix Asphalt, Funding source: Federal Highway Administration (in Collaboration with Delft University of Technology)

 Compaction is the process of reducing the volume of hot mix asphalt (HMA) under the action of external forces.  The quality of field compaction of HMA is one of the most important aspects that influence asphalt pavement performance.  Poor compaction has been associated with asphalt bleeding in hot weather environments, moisture damage, excessive aging and associated cracking, and premature permanent deformation.  This project aims at the development of a mathematical model for HMA compaction and the implementation of this model in finite element in order to be used for predicting the compaction of asphalt mixtures under laboratory and field conditions. 

Simulation of Asphalt Mixture Compaction in the Laboratory.

Last modified   August, 2012