PREDICTION OF ANISOTROPIC RESILIENT RESPONSES FOR UNBOUND GRANULAR LAYER CONSIDERING AGGREGATE PHYSICAL PROPERTIES AND MOVING WHEEL LOAD
A simple procedure is proposed to account for the effects of aggregate gradation and shape properties in predicting the cross-anisotropic modular ratio of unbound granular layers. Variable confining pressure type repeated triaxial were performed, following the International Center for Aggregates Research (ICAR) testing protocol, on six aggregate sources with three different gradations (coarse, well and fine) and three different moisture contents (wet, optimum and dry). The experimental results were analyzed within the framework of a cross-anisotropic nonlinear elastic model and the model coefficients were determined. The image analysis technique was used to measure aggregate shape properties and the three-parameter equation was accommodated to fit the cumulative distribution of aggregate gradation. The gradation and shape properties of the three aggregates were fitted using a nonlinear regression model which is capable of capture the complete distribution of these properties. The cross-anisotropic material coefficients of unbound granular bases were in turn related to the particle size distribution, dry density and aggregate shape. This approach provides a tool to help understand the relationship among anisotropic resilient behavior of aggregate bases, aggregate physical properties and environmental conditions. A newly developed approach for determining cross-anisotropic modular ratio in the aggregate base indicates that the vertical resilient modulus is generally greater than the horizontal resilient modulus and this anisotropic resilient behavior has substantial effect on the critical pavement responses. Thus, it is extremely useful to approximate the degree of cross-anisotropy in unbound aggregates in order to adequately model unbound aggregate bases for pavement design and analysis.
- Record URL:
-
Corporate Authors:
University of Texas, Austin
International Center for Aggregates Research, 3208 Red River
Austin, TX United States 78705-2650 -
Authors:
- Kim, S-H
- Little, D N
- Masad, E
- Lytton, R L
-
Conference:
- Aggregates: Asphalt Concrete, Portland Cement Concrete, Bases, and Fines. Twelfth Annual Symposium
- Location: Denver, Colorado
- Date: 2004-4-4 to 2004-4-7
- Publication Date: 2004-4
Language
- English
Media Info
- Features: Figures; References; Tables;
- Pagination: 24p
Subject/Index Terms
- TRT Terms: Aggregate gradation; Aggregates; Anisotropic materials; Base course (Pavements); Confining pressure; Dry density; Granular bases; Image analysis; Moisture content; Particles; Pavement design; Pavement layers; Physical properties; Regression analysis; Resilience (Materials); Shape; Wheel loads
- Subject Areas: Data and Information Technology; Geotechnology; Highways; Pavements; I23: Properties of Road Surfaces; I36: Aggregates;
Filing Info
- Accession Number: 00976606
- Record Type: Publication
- Files: TRIS
- Created Date: Jul 7 2004 12:00AM