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Title:

Conversion of Testing Frequency to Loading Time: Impact on Performance Predictions Obtained from Mechanistic-Empirical Pavement Design Guide

Accession Number:

01023241

Record Type:

Component

Availability:

Transportation Research Board Business Office

500 Fifth Street, NW
Washington, DC 20001 United States

Abstract:

This paper examines the impact on performance prediction of the erroneous conversion of the dynamic modulus master curve from frequency domain to time domain inherent in the NCHRP 1-37A Mechanistic-Empirical Pavement Design Guide (MEPDG). The new Simple Performance Test (SPT) is used in determination of the dynamic (complex) modulus ?ìE*?ì for input to the MEPDG. Testing is conducted at selected temperatures and frequencies. ?ìE*?ì as a function of frequency for a total of six frequencies (0.1, 0.5, 1, 5, 10, 25 Hz) are input in the MEPDG software. From this data the MEPDG generates an ?ìE*?ì master curve as a function of frequency first and then erroneously converts it to a function of loading time. The error in determining loading time during master curve generation is that frequency, f, in Hz is directly converted to loading time, t, in seconds by taking the inverse of f (i.e. t = 1/f). The choice of the unit of frequency (Hz vs. rad/s) is very important when converting from frequency domain to loading time domain. The most widely used (correct) approach in Rheology is to first convert the cyclic frequency in Hz (f) to angular frequency in radians/s (?ç, rad/s = 2?àf) and then taking the inverse to determine loading time (t=1/2?àf). The effect of the two methods of frequency to time conversion on the pavement performance predicted using the MEPDG is studied in this paper. From this analysis and related literature review, recommendations are made about correct frequency to time conversion methods and appropriate use of ?ìE*?ì.

Monograph Accession #:

01020180

Report/Paper Numbers:

06-2394

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

D''Angelo, John A
Dongre, Raj N
Myers, Leslie Ann

Pagination:

16p

Publication Date:

2006

Conference:

Transportation Research Board 85th Annual Meeting

Location: Washington DC, United States
Date: 2006-1-22 to 2006-1-26
Sponsors: Transportation Research Board

Media Type:

CD-ROM

Features:

Figures (6) ; References (10) ; Tables (3)

Subject Areas:

Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways

Source Data:

Transportation Research Board Annual Meeting 2006 Paper #06-2394

Files:

BTRIS, TRIS, TRB

Created Date:

Mar 3 2006 10:58AM