United States Department of Transportation
[PDF-891.33 KB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Edition:Final report; Jan. 2007-June 2009.
-
Corporate Publisher:
-
Abstract:One of the most critical parameters needed for the upcoming Mechanistic Empirical Pavement Design Guide
(MEPDG) is the dynamic modulus (E*), which will be used for flexible pavement design. The dynamic modulus
represents the stiffness of the asphalt material when tested in a compressive-type, repeated load test. The
dynamic modulus is one of the key parameters used to evaluate both rutting and fatigue cracking distresses in
the MEPDG. The computer software that accompanies the MEPDG also provides general default parameters for
the dynamic modulus (i.e. – Level 2 and 3 inputs). However, caution has already been issued by the National
Cooperative Highway Research Program (NCHRP) researchers as to the appropriateness of these parameters
for regional areas. The major concern is that state agencies will use these default values blindly and sacrifice
accuracy of the design. Hence, making the new mechanistic procedure no better than using a structural number
(SN) with the old AASHTO method.
There were three primary objectives of the research study. First, the current version of the dynamic modulus
test, AASHTO TP62-07, was evaluated to determine the relative precision of the test method, and if required,
recommend a modified procedure with better precision. The second objective of the study was to develop a
dynamic modulus catalog for use with the Mechanistic Empirical Pavement Design Guide (MEPDG) by testing
plant-produced and laboratory-compacted samples of various asphalt mixtures. This would supercede Level 2
inputs currently in the MEPDG for New Jersey. The third primary objective of the research study was to assess
the accuracy of two commonly utilized dynamic modulus prediction equations; 1) Witczak Prediction Equation
and 2) Hirsch Model. The database developed during the study also led to the development of correlations
between dynamic modulus and fatigue cracking and rutting performance of asphalt mixtures.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
