Civil and Environmental Engineering Commons^™

Dense-Graded Aggregate Base Gradation Influencing Rutting Model Predictions, Issam I.A. Qamhia, Liang Chern Chow, Debakanta Mishra, Erol Tutumluer

Debakanta Mishra

This paper presents findings from an ongoing research study at the University of Illinois focused on developing and calibrating an improved permanent deformation model for unbound aggregate materials through laboratory testing and characterization. The project scope included testing sixteen aggregate materials, commonly used in the state of North Carolina for pavement base courses, in the laboratory through monotonic and repeated load triaxial testing. This paper primarily focuses on quantifying effects of aggregate gradation on permanent deformation behavior. To accomplish this, four materials were tested at both: (1) “source gradations,” i.e. original gradations from quarry, and (2) an “engineered gradation,” i.e., …

Use Of Multidepth Deflectometers And Strain Gauges To Investigate The Differential Movement At Railway Bridge Approaches, D. Mishra, E. Tutumluer, H. Kazmee, H. Boler

Debakanta Mishra

Investigation Of Ballast Degradation And Fouling Trends Using Image Analysis, M. Moaveni, Y. Qian, H. Boler, D. Mishra, E. Tutumluer

Debakanta Mishra

Ballast fouling, often associated with deteriorating railroad track performance, refers to the condition when the ballast layer changes its composition and becomes much finer in grain size distribution. This paper describes an image analysis approach to characterize different stages of railroad ballast degradation studied using Los Angeles abrasion testing in the laboratory. An aggregate image analysis approach is utilized to investigate ballast particle abrasion and breakage trends at every stage through detailed quantifications of individual ballast particle size and shape properties. Aggregate image processing or segmentation techniques have been also developed and used in this study to analyze the two-dimensional …

Field Performance Evaluations Of Illinois Aggregates For Subgrade Replacement And Subbase—Phase Ii, Debakanta Mishra, Erol Tutumluer

Debakanta Mishra

The project objective was to validate the results from ICT Project R27-1, which characterized in the laboratory the strength, stiffness, and deformation behaviors of three different aggregate types commonly used in Illinois for subgrade replacement and subbase applications, through accelerated loading of full-scale pavement working platform test sections. Six different test “cells” were constructed at different combinations of aggregate material quality and subgrade strength, and were tested to failure using the University of Illinois Accelerated Transportation Loading Assembly (ATLAS). Each cell was tested along two different wheel paths representing two different aggregate layer moisture contents (Cells 1-5), or geotextile reinforcement …

Investigation And Mitigation Of Differential Movement At Railway Transitions For Us High Speed Passenger Rail And Joint Passenger/Freight Corridors, Erol Tutumluer, Timothy D. Stark, Debakanta Mishra, James P. Hyslip

Debakanta Mishra

As with most highway bridges, railway transitions experience differential movements due to differences in track system stiffness, track damping characteristics, foundation type, ballast settlement from fouling and/or degradation, as well as fill and subgrade settlement. This differential movement is especially problematic for high speed rail infrastructure as the “bump” at the transition is accentuated at high speeds. Identification of different factors contributing towards this differential movement, as well as development of design and maintenance strategies to mitigate the problem is imperative for the safe and economical operation of both freight and passenger rail networks. This paper presents the research framework …

Laboratory And Field Measured Moduli Of Unsurfaced Pavements On Weak Subgrade, Debakanta Mishra, Erol Tutumluer, Maziar Moaveni, Yuanjie Xiao

Debakanta Mishra

This paper presents findings on the effectiveness of field modulus determinations and modulus based assessment of constructed pavement foundation geomaterials, i.e. subgrade soil and base/subbase unbound aggregate material. Full-scale unsurfaced pavement test sections were constructed on controlled strength weak subgrades and tested to failure for studying effects of aggregate quality on pavement performance. Differences in aggregate quality were assessed by changes in aggregate properties such as particle angularity, fines content and plasticity of fines. In-situ moduli of the constructed layers were measured using both light weight deflectometer (LWD) and GeoGauge^TM type field devices. Tests were conducted on the engineered …

Particle Shape, Type And Amount Of Fines, And Moisture Affecting Resilient Modulus Behavior Of Unbound Aggregates, Debakanta Mishra, Erol Tutumluer, Yuanjie Xiao

Debakanta Mishra

This paper presents the application of Analysis of Variance (ANOVA) approach to study effects of different aggregate properties on the resilient modulus behavior of unbound aggregates. In a recent research project at the University of Illinois, stress-dependent resilient modulus characterization models, in the form proposed for use by the Mechanistic Empirical Pavement Design Guide (MEPDG), were established for three different aggregate types (dolomite, limestone, and uncrushed gravel) using a statistically well-formulated laboratory test matrix. Such a consistent database enabled the evaluation of the model parameter dependence on different aggregate properties, such as particle shape, type and amount of fines, and …

Characterization Of Illinois Aggregates For Subgrade Replacement And Subbase, Erol Tutumluer, Debakanta Mishra, Abbas A. Butt

Debakanta Mishra

Construction of a pavement working platform is often needed on soft, unstable soils to provide sufficient stability and adequate immediate support for equipment mobility and paving operations without developing excessive rutting. The aggregate type and quality are important factors for determining the required treatment/ replacement thickness. The overall objective in this project has been to characterize strength, stiffness, and deformation behavior of three crushed and uncrushed aggregate materials, i.e., limestone, dolomite and uncrushed gravel, commonly used in Illinois for subgrade replacement and subbase. The goal has been to develop aggregate thickness correlations with aggregate properties to modify and improve the …

Water Intrusion In Base/Subgrade Materials At Bridge Ends, Priyantha Jayawickrama, Phil Nash, Michael Leaverton, Debakanta Mishra

Debakanta Mishra

Departments of transportation spend considerable time and money repairing pavement failures that occur in the base or subgrade materials near bridge ends. Investigation of these failures often reveal saturated base/subgrade materials. The objectives of this research were to determine all possible sources for water intrusion, develop methods to recognize in-the-field causes of water collection at bridge approaches, and to develop new repair methods that can be economically implemented in the field to minimize water intrusion or remove water from soils.

Research focused on existing bridge approaches, concentrated on maintenance techniques to prevent water intrusion at bridge ends, and included an …