Details:

Creators:
Zhang, Yuqing ; Luo, Rong ; Lytton, Robert L.
Zhang, Yuqing ; Luo, Rong ; Lytton, Robert L. Less -
Corporate Creators:
Texas A&M Transportation Institute
Corporate Contributors:
University Transportation Centers Program (U.S.)
Subject/TRT Terms:
[+]
Anisotropy (Physics) Asphalt Mixtures Asphalt Pavements Compression Laboratory Tests Mathematical Models Pavement Distress Rutting Viscoplasticity
Publication/ Report Number:
SWUTC/13/600451-00006-1
Resource Type:
Tech Report
Geographical Coverage:
United States
Corporate Publisher:
Southwest Region University Transportation Center (U.S.)
Abstract:
Permanent deformation (i.e., rutting) is one of the major distresses in asphalt pavements, and it consists of

irrecoverable deformation due to viscoplastic flow and viscofracture fatigue damage. The mechanisms of rutting have not

been well addressed due to the complexities of asphalt mixture including (a) distinctions between compression, extension,

and tension; (b) rate and temperature dependence; (c) dilative volumetric change; (d) frictional material with cohesion;

(e) inherent anisotropy due to preferential aggregates’ orientation; (f) crack-induced anisotropy due to crack growth;

(g) strain hardening during viscoplastic accumulation; and (h) strain softening during viscofracture evolution.

In this project, all of the aforementioned fundamentals of asphalt mixtures were simultaneously characterized by a

comprehensive viscoplastic-fracture mechanistic model, which was incorporated with (a) a modified effective stress to

consider the inherent anisotropy and the crack-induced anisotropy due to viscofracture cracking in compression; (b) a

smooth and convex Generalized Drucker-Prager (GD-P) yield surface; (c) a non-associated viscoplastic flow rule; (d) a

rate- and temperature-dependent strain hardening rule; and (e) a viscofracture evolution that was modeled by an

anisotropic damage density-based pseudo J-integral Paris’ law. The model parameters were related to fundamental material

properties that were measurable and understandable for civil engineers. A systemic testing protocol including five

individual test methods were proposed to determine the model parameters and material properties. The test protocol was

demonstrated to be efficient, as one asphalt mixture could be completely characterized within 1 day. The GD-P yield

surface model was validated by octahedral shear strength tests at different normal and confining stresses. The GD-P model

was able to characterize the full range of the internal friction angles from 0 to 90 degrees. In contrast, the widely used

Extended Drucker-Prager (ED-P) model can only be used for a material that has an internal friction angle less than 22

degrees due to the convexity criterion of the yield surface.


Format:
PDF
Funding:
DTRT12-G-UTC06
Collection(s):
US Transportation Collection University Transportation Centers
Main Document Checksum:
[+]
urn:sha256:dcffc61e49a5953a46010b5d6471cb438f9c24c1d6101d925d89d33d32730d8f
Download URL:
https://rosap.ntl.bts.gov/view/dot/26647/dot_26647_DS1.pdf
File Type:

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