Journal ArticleDOI
Evaluation of Dynamic Earth Pressure Cells for Subgrade
TLDR
In this article, two types of commercially available dynamic earth pressure cells were tested to determine their suitability for measuring traffic-induced stresses in subgrade, and the main consideration was how well the gauges could be calibrated for accurate representation of soil stresses.Abstract:
Two types of commercially available dynamic earth pressure cells were tested to determine their suitability for measuring traffic-induced stresses in subgrade. The main consideration was how well the gauges could be calibrated for accurate representation of soil stresses. Tests were conducted with fluid pressure applied directly to the cells and with cells buried at various depths in a soil test chamber. The effects of soil type, proximity of adjacent cells, major principal stress direction, and temperature were investigated. Results indicate linearity, hysteresis, sensitivity, conformance, and accuracy. The two cells performed differently, but one was much more accurate than the other.read more
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Evaluation of geosynthetic reinforced flexible pavement systems using two pavement test facilities
Abstract: Montana State University has previously competed experimental test section, numerical modeling and design model development projects for the Montana Department of Transportation. Test section work has led to a fundamental understanding of mechanisms by which geosynthetics provide reinforcement when placed in the aggregate layer of flexible pavements. Finite element numerical models have relied upon this knowledge as their basis while design models derived from these numerical models have been calibrated against results from test sections. The test sections used for the development of these models were limited by the number of subgrade types, geosynthetic types and loading type employed. This project was initiated to provide additional test section data to better define the influence of traffic loading type and geosynthetic reinforcement type. The loading provided to the test sections forming the basis of the models described above consisted of a cyclic load applied to a stationary plate. In this project, four full-scale test sections were constructed and loaded with a heavy vehicle simulator (HVS) located at the US Army Corp of Engineers facility in Hanover, NH. The four test sections used three geosynthetics identical to those used in previous test sections and pavement layer materials and thickness similar to previous sections. Additional test sections were constructed in the pavement test box used in previous studies to examine the influence of base aggregate type, base course thickness reduction levels and reinforcement type. A rounded pit run aggregate was used in test sections to evaluate the influence of geosynthetic-aggregate shear interaction parameters on reinforcement benefit. The 1993 AASHTO Design Guide was used to backcalculate the base course thickness reduction from previous test section results where a traffic benefit ratio (extension of life) was known. Sections were built to this base course thickness reduction to see if equivalent life to an unreinforced section was obtained. Finally, six different geosynthetic products were used in test sections to evaluate the influence of reinforcement type on pavement performance. The four test sections loaded with the HVS tended to show pavement distress that was dominated by surface rutting due to the development of permanent strain in the asphalt concrete, base aggregate and subgrade layers. Several asphalt cracking areas were due to delamination between the binder and surface courses. The order of performance of the test sections generally followed that seen in previous studies. An evaluation of reinforcement benefit in terms of rutting behavior was complicated by the …
Journal ArticleDOI
Evaluation of base-reinforced pavements using a heavy vehicle simulator
S. W. Perkins,E. R. Cortez +1 more
TL;DR: In this article, four full-scale flexible pavement test sections were constructed to evaluate pavement performance containing three geosynthetic reinforcement products, and a significant improvement in rutting due to the development of permanent strain in the pavement and soil layers, was observed in all reinforced sections.
The development and verification of a pavement response and performance model for unbound granular pavements
Abstract: ........................................................................................................................i Acknowledgements ......................................................................................................ii Dedication ....................................................................................................................ii Chapter
Dissertation
Utilization of Instrument Response of SuperPaveTM Mixes at the Virginia Smart Road to Calibrate Laboratory Developed Fatigue Equations
TL;DR: In this article, four shift factors were identified to correlate field and lab fatigue behavior: stress-state, material difference, traffic wander, and healing, and the derived shift factors utilize the measured stresses and strains at the Virginia Smart Road, calculated strains and stresses, based on appropriate pavement and loading modeling.
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Journal ArticleDOI
Soil Stress Gage Calibration
TL;DR: In this article, an easy-to-construct and inexpensive fluid calibration chamber for soil stress gages is described, and a suggested soil calibration facility is also described to illustrate the type of information that can be obtained.