Erol Tutumluer


Erol Tutumluer is a Professor specializing in transportation and geotechnical engineering in the Department of Civil and Environmental Engineering (CEE) at the University of Illinois at Urbana-Champaign (UIUC). He completed his B.S. at Bogazici University (1989), two M.S. degrees (Duke University 1991 and Georgia Tech 1993), and a Ph.D. (Georgia Tech 1995), all in civil engineering. He joined the UIUC faculty as an Assistant Professor in 1996. Professor Tutumluer teaches graduate and undergraduate courses in transportation soils engineering, subgrade soil and aggregate behavior and stabilization, pavement analysis and other transportation engineering courses. He has expertise in testing and modeling of railroad track and pavement geo-materials, such as base/ballast unbound aggregates, recycled aggregates and their unbound applications, shape, texture, angularity characterization of aggregates using video-imaging techniques, use of geosynthetics in pavements/railroad track, modeling of particulate media using discrete and finite element methods, artificial intelligence in the form of neural network modeling, mechanistic based pavement design, and nondestructive pavement evaluation. Dr. Tutumluer is currently working on four different railroad ballast research projects: 
(1) Discrete Element Modeling of Ballast funded by the AAR Technology Scanning Program, 
(2) Railroad Track Substructure Evaluation jointly funded by AAR and the FRA, 
(3) Investigation of Fouled Ballast Behavior funded by the BNSF Railway, and 
(4) Testing of Polyurethane Elastomer Coated Railroad Ballast funded by BASF.

Dr. Tutumluer was the recipient of the Transportation Research Board (TRB) Fred Burggraf award for Excellence in Transportation Research in 2000, and he received the Best Paper Award from the Geology and Properties of Earth Materials Section of TRB in 2009. He is an affiliate member of TRB and has chaired its AFS50(1) subcommittee on Applications of Nontraditional Computing Tools Including Neural Nets and also serves on TRB committees AFP70, AFP30, AFS50, and AFD80. He is also a member of the American Railway Engineering and Maintenance of Way Association Committee 1 on "Ballast." He is chair of the American Society of Civil Engineering (ASCE) Geo-Institute's Pavements Committee and the co-editor of five ASCE Geotechnical Special Publications on recent advances in transportation materials characterization, pavement engineering, and pavement mechanics and testing. Dr. Tutumluer is a member of the Editorial Board of the International Journal of Pavement Engineering, and the ASCE International Journal of Geomechanics. He is also an Associate Editor of the International Journal of Pavement Research and Technology, and the ASCE Journal of Computing in Civil Engineering. He served as the Conference Chair and Proceedings Co-editor of the 8th International Conference on the Bearing Capacity of Roads, Railways and Airfields (BCR2A'09) which was held at the University of Illinois in 2009. For his teaching and scholarly service, Dr. Tutumluer was named a General Electric Scholar by the UIUC College of Engineering in 1997 and later that year received a certificate of recognition as an Engineering Education Scholar by the National Science Foundation. Subsequently, he was named General Electric Fellow (1999) and Collins Fellow (2000) by the Academy of Excellence in Engineering Education program administered by the College of Engineering; elected as a Campus Honors Program faculty member by the Chancellor of UIUC (2001); and listed in the campus incomplete list of teachers ranked as excellent by their students (2003 and 2008) at UIUC. In 2006, Dr. Tutumluer was recognized with the Endowed Paul F. Kent Faculty Scholarship for his research accomplishments in the CEE Department at UIUC and in 2008 he was promoted to full Professor.


A large portion of the annual budget to sustain the railway track system goes into maintenance and renewal of ballast. Better understanding of ballast behavior as it is influenced by aggregate type, gradation, angularity, and surface texture properties is essential for mitigating track problems and improving track safety and performance. Failures can occur due to ballast fouling, ballast deformation and degradation due to compaction and repeated loading, and ballast lateral movement and instability that can cause track buckles. To provide better insight regarding the engineering design of ballasted track, current research at the University of Illinois is focused on development of a ballast performance model using Discrete Element Modeling (DEM). DEM uses rigid, randomly shaped "blocks" as the basic elements to realistically simulate interactions such as interlock and contact between individual aggregate particles. The ballast DEM also uses the University of Illinois Aggregate Image Analyzer (UIAIA) with algorithms for image-based aggregate shape characterization and has been calibrated by conducting shear box tests of ballast strength in the laboratory. Recent research efforts have focused on validating the ballast DEM in the field using settlement records of different ballast test sections constructed at the Facility for Accelerated Service Testing (FAST) for Heavy Axle Load (HAL) applications at the Transportation Technology Center (TTC) in Pueblo, Colorado. Although there is room to incorporate aggregate breakage and particle crushing into the DEM model in future development, preliminary results from the dynamic, repeated train loading simulations conducted at FAST indicate that the ballast DEM model can predict magnitudes of field ballast settlement from initial loading cycles to over 100 MGT reasonably accurately. These ballast settlement predictions are sensitive to both aggregate shape and gradation.

Field Validated Model for Predicting Railroad Ballast Behavior