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|Title:||Mechanistic Interpretation of Nondestructive Pavement Testing Deflections|
|Author(s):||Hoffman, Mario Sergio|
|Department / Program:||Civil Engineering|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||A method is proposed for the backcalculation of material properties in flexible pavements based on the interpretation of surface deflection measurements. ILLI-PAVE, a stress-dependent finite element pavement model, was used to generate data for developing algorithms and nomographs for deflection basin interpretation.
Over 11,000 deflection measurements for 24 different flexible pavement sections throughout the State of Illinois were collected and analyzed. Deflections were measured using the Benkelman Beam, the IDOT Road Rater, the Falling Weight Deflectometer, and an accelerometer to measure deflections under moving trucks. Loading mode effects on pavement response were investigated using dynamic and viscous pavement models. The factors controlling the pavement response to different loading modes were explained and identified. Correlations between different devices were developed. The study indicated that the Falling Weight Deflectometer response best simulates pavement response under a moving truck. The Road Rater, because of its harmonic loading without rest periods and the static superimposed load, induces a stiffened response of the pavement-subgrade system. The quasi-static loading in Benkelman Beam testing induces the highest deflections in most pavements.
The proposed evaluation procedure is illustrated for three different flexible pavements using deflection data collected on several testing dates. Agreement is achieved between back-calculated material properties and laboratory determined properties. Agreement is also obtained between measured and predicted deflection basins. The backcalculated parameters using the proposed evaluation procedure can be used as input for overlay design. The change in the stress state in the pavement-subgrade system effected by a change in the pavement cross section (overlay) is accounted for by the nonlinear stress-dependent characterization of the granular base material and subgrade soil in the ILLI-PAVE structural pavement model.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.
|Date Available in IDEALS:||2014-12-13|
This item appears in the following Collection(s)
Dissertations and Theses - Civil and Environmental Engineering
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois