Validated Model for Predicting Field Performance of Aggregate Base Courses

2003 ◽  
Vol 1837 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Erol Tutumluer ◽  
Dallas N. Little ◽  
Sung-Hee Kim
Keyword(s):  
Permanent Deformation ◽  
Field Performance ◽  
Stress Sensitivity ◽  
Triaxial Tests ◽  
Validation Data ◽  
Finite Element Program ◽  
University Of Illinois ◽  
Aggregate Base ◽  
The University ◽  
Unbound Aggregate

The International Center for Aggregates Research Project 502 focused on pavement layers of unbound aggregate proper representation in mechanistic pavement models. The research team developed models for resilient and permanent deformation behavior from the results of triaxial tests conducted at the Texas Transportation Institute and the University of Illinois. The studies indicate that the unbound aggregate base (UAB) material should be modeled as nonlinear and cross-anisotropic to account for stress sensitivity and the significant differences between vertical and horizontal moduli and Poisson’s ratios. Field validation data were collected from a full-scale pavement test study conducted at Georgia Tech. The validation of the anisotropic modeling approach was accomplished by analyzing conventional flexible pavement test sections using the GT-PAVE finite element program to predict responses to load in the UAB layer and comparing these predicted responses to the measured values. Laboratory testing of the aggregate samples was conducted at the University of Illinois, and characterization models were developed for the stress-sensitive, cross-anisotropic aggregate behavior. With nonlinear anisotropic modeling of the UAB, the resilient behavior of pavement test sections was successfully predicted for a number of response variables. In addition, the stress-sensitive, cross-anisotropic representation of the base was shown to greatly reduce the horizontal tension computed in the granular base compared with a linear isotropic representation.

scholarly journals Applicability of Modified University of Illinois at Urbana–Champaign Model for Unbound Aggregate Material with Different Water Content

2019 ◽  
Vol 2673 (3) ◽  
pp. 439-449
Author(s):  
Tianshu Lin ◽  
Tatsuya Ishikawa ◽  
Bin Luo
Keyword(s):  
Shear Strength ◽  
Deformation Behavior ◽  
Permanent Deformation ◽  
Critical Factor ◽  
Shear Loading ◽  
Stress Axis ◽  
Test Results ◽  
Loading Test ◽  
University Of Illinois ◽  
Unbound Aggregate

This paper proposes a modified University of Illinois at Urbana–Champaign (UIUC) model to predict permanent deformation behavior of unbound aggregate materials. Most existing models relate permanent deformation to resilient properties, whereas the UIUC model treats shear strength as a critical factor in permanent deformation behavior. Three types of test, monotonic shearing test, cyclic axial loading test, and cyclic axial and shear loading test, were conducted by multi-ring shear apparatus on two kinds of parallel grading aggregate materials, natural crusher-run and recycled crusher-run obtained from demolished concrete structure. Test results demonstrate that shear strength is the core factor in permanent deformation behavior, compared with resilient properties, and principal stress axis rotation (PSAR) greatly increases the permanent deformation. By considering the effect of PSAR on permanent deformation, a new parameter, ( Rs)ave, is added to the conventional UIUC model to modify it. Regression analysis results verify that the modified UIUC model has good applicability for predicting permanent deformation of aggregates with different water contents and stress states, and with and without PSAR. The modified UIUC model builds a relation between test results with and without PSAR. A simple framework is also proposed for predicting permanent deformation in flexible pavement structures based on the modified UIUC model.

Unbound Aggregate Rutting Models for Stress Rotations and Effects of Moving Wheel Loads

2005 ◽  
Vol 1913 (1) ◽  
pp. 41-49 ◽  
Author(s):  
In Tai Kim ◽  
Erol Tutumluer
Keyword(s):  
Test Data ◽  
Permanent Deformation ◽  
Confining Pressure ◽  
Stress Path ◽  
In Situ Stress ◽  
Triaxial Tests ◽  
Wheel Loading ◽  
Stress States ◽  
Granular Layers ◽  
Unbound Aggregate

The latest research findings on stress rotations caused by moving wheel loads and their effects on permanent deformation or rut accumulation in pavement granular layers are presented. Realistic pavement stresses induced by moving wheel loads were examined in the unbound aggregate base and subbase layers, and the significant effects of rotation of principal stress axes were indicated for a proper characterization of the permanent deformation behavior. To account for the rutting performances of especially thick granular layers, a comprehensive set of repeated load triaxial tests was conducted in the laboratory. Triaxial test data were obtained and analyzed from testing aggregates under various realistic in situ stress paths caused by moving wheel loading. Permanent deformation characterization models were then developed on the basis of the experimental test data to include the static and dynamic stress states and the slope of stress path loading. The models that also considered the stress path slope variations predicted the stress path dependency of permanent deformation accumulation best. In addition, multiple stress path tests conducted to simulate the extension–compression–extension type of rotating stress states under a wheel pass gave much higher permanent strains than those of the compression-only single path tests. The findings indicated actual traffic loading simulated by the multiple path tests could cause greater permanent deformations or rutting damage, especially in the loose base or subbase, when compared with deformations measured from a dynamic plate loading or a constant confining pressure type laboratory test.

Five Decades of Research Experience in Speech Anatomy and Physiology

2016 ◽  
Vol 1 (5) ◽  
pp. 4-12
Author(s):  
David P. Kuehn
Keyword(s):  
Ohio State University ◽  
State University ◽  
Research Experience ◽  
University Of Iowa ◽  
University Of Illinois ◽  
Anatomy And Physiology ◽  
The Ohio State University ◽  
Speech Science ◽  
The University ◽  
East Carolina University

This report highlights some of the major developments in the area of speech anatomy and physiology drawing from the author's own research experience during his years at the University of Iowa and the University of Illinois. He has benefited greatly from mentors including Professors James Curtis, Kenneth Moll, and Hughlett Morris at the University of Iowa and Professor Paul Lauterbur at the University of Illinois. Many colleagues have contributed to the author's work, especially Professors Jerald Moon at the University of Iowa, Bradley Sutton at the University of Illinois, Jamie Perry at East Carolina University, and Youkyung Bae at the Ohio State University. The strength of these researchers and their students bodes well for future advances in knowledge in this important area of speech science.

University Geographies and Folk Music Landscapes

2016 ◽  
Vol 33 (1) ◽  
pp. 92-116 ◽  
Author(s):  
David K. Blake
Keyword(s):  
Mass Culture ◽  
Folk Music ◽  
Traditional Music ◽  
Rural Landscape ◽  
Power Structures ◽  
Distant Object ◽  
University Of Illinois ◽  
Liberal Politics ◽  
Cultural Form ◽  
The University

By examining folk music activities connecting students and local musicians during the early 1960s at the University of Illinois at Urbana-Champaign, this article demonstrates how university geographies and musical landscapes influence musical activities in college towns. The geography of the University of Illinois, a rural Midwestern location with a mostly urban, middle-class student population, created an unusual combination of privileged students in a primarily working-class area. This combination of geography and landscape framed interactions between students and local musicians in Urbana-Champaign, stimulating and complicating the traversal of sociocultural differences through traditional music. Members of the University of Illinois Campus Folksong Club considered traditional music as a high cultural form distinct from mass-culture artists, aligning their interests with then-dominant scholarly approaches in folklore and film studies departments. Yet students also interrogated the impropriety of folksong presentation on campus, and community folksingers projected their own discomfort with students’ liberal politics. In hosting concerts by rural musicians such as Frank Proffitt and producing a record of local Urbana-Champaign folksingers called Green Fields of Illinois (1963), the folksong club attempted to suture these differences by highlighting the aesthetic, domestic, historical, and educational aspects of local folk music, while avoiding contemporary socioeconomic, commercial, and political concerns. This depoliticized conception of folk music bridged students and local folksingers, but also represented local music via a nineteenth-century rural landscape that converted contemporaneous lived practice into a temporally distant object of aesthetic study. Students’ study of folk music thus reinforced the power structures of university culture—but engaging local folksinging as an educational subject remained for them the most ethical solution for questioning, and potentially traversing, larger problems of inequality and difference.

The Early Years of the Jewish Presence at the University of Illinois

1992 ◽  
Vol 2 (2) ◽  
pp. 215-245
Author(s):  
Winton U. Solberg
Keyword(s):  
Higher Education ◽  
The United States ◽  
Early Years ◽  
Late Nineteenth Century ◽  
Characteristic Form ◽  
University Of Illinois ◽  
American Higher Education ◽  
Jewish Students ◽  
The University ◽  
The Church

For over two centuries, the College was the characteristic form of higher education in the United States, and the College was closely allied to the church in a predominantly Protestant land. The university became the characteristic form of American higher education starting in the late nineteenth Century, and universities long continued to reflect the nation's Protestant culture. By about 1900, however, Catholics and Jews began to enter universities in increasing numbers. What was the experience of Jewish students in these institutions, and how did authorities respond to their appearance? These questions will be addressed in this article by focusing on the Jewish presence at the University of Illinois in the early twentieth Century. Religion, like a red thread, is interwoven throughout the entire fabric of this story.

Sign in / Sign up

Export Citation Format

Share Document