Environmental Effects in Pavement Mix and Structural Design Systems

[mahyarov]

Environmental Effects in Pavement Mix and Structural Design Systems

Author: Houston, William N | Size: 2.26 MB | Format: PDF | Quality: Original preprint | Publisher: Transportation Research Board | Year: 2005 | pages: 298 | ISBN: -

It is well documented that environmental effects play a significant role in characterizing the material properties, which in turn affect the pavement performance. Studies under the Strategic Highway Research Program (SHRP) were carried out to study the age hardening characteristics of asphalt binders and mixes. As a result of this study, laboratory procedures American Association of State Highway and Transportation Officials, provisional protocols (AASHTO PP1-98 and PP2-99) were developed to study the hardening potential of asphalt binders and mixes. The approaches followed in these procedures are of great value for the ongoing research on pavement aging; however, due to the limited resources and time constraints under the SHRP program, these provisional procedures have certain limitations associated with them. Research study, National Cooperative Highway Research Program (NCHRP) 9-23 was initiated to assess these limitations and if possible, enhance the predictive capabilities of these protocols. Binders and field cores were obtained from LTPP sections and other sites across the United States. Original, laboratory-aged, and field-aged binders were characterized. Based on the findings, an alternate procedure to the AASHTO PP1-98 protocol is suggested and presented. The alternate procedure includes field aging conditions and volumetric properties of the mix. The model developed was calibrated and validated using the data obtained from the field cores. Parametric analysis was performed on the final model to ascertain the practicality of the output. The assessment of the existing PP2-99 test protocol is also presented. Asphalt mix cores aged in the laboratory were tested for complex modulus. These modulus values were then compared to the modulus values of the field cores, the ages of which were known from the construction records. Due to the limited amount of data available, the PP2-99 protocol could not be improved.

Code:

***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:

http://forum.civilea.com/thread-27464.html
***************************************

This post has been made by CivilEA Post-Generator ver 2.1.6