Atterberg limits and their relationship to longitudinal cracking in granular pavements

Stanton, Dale John (2010) Atterberg limits and their relationship to longitudinal cracking in granular pavements. [USQ Project] (Unpublished)

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Abstract

[Abstract]: Australia has approximately 300,000km of sealed roads and maintenance of these roads imposes a significant financial burden on road agencies. Premature pavement failure exacerbates this burden. Longitudinal pavement cracking often occurs independent of traffic loading and may be attributed in many instances to moisture changes in expansive subgrade soils. This project investigates a possible relationship between the Atterberg limits of low strength subgrade materials (CBR < 3) and the incidence of longitudinal cracking in unbound granular (flexible) pavements supported by them. Unbound granular pavements are the most common form of pavement construction in Australia. Design of these pavements is undertaken in accordance with individual authorities’ empirical design charts. These design charts are usually presented as a series of curves whereby the depth of pavement is set by the relationship between subgrade strength, expressed in terms of a four day soaked California Bearing Ratio (CBR) and traffic loading over the pavement’s design life, expressed in Equivalent Standard Axles (ESAs). These charts typically provide pavement depths for subgrade CBR values of 3 and above. Where the subgrade CBR is less than 3, the guidelines recommend an additional depth of pavement gravel depending on the CBR. The primary objective of this research is to determine if any of the Atterberg limits can be used as a predictor of longitudinal cracking in unbound granular pavements designed in accordance with authority guidelines. This would enable consultants and authorities to determine if alternate methods of pavement construction should be considered (using tensile reinforcement for example) in lieu of unbound granular construction. Analysis of results indicated that a relationship exists between two of the Atterberg limits of a subgrade material and longitudinal cracking in unbound granular pavements designed in accordance with existing authority empirical design charts. Due to the small sample size, recommendation on specific values of these limits to determine when alternate pavement designs should be considered would be premature.


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Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Depositing User: epEditor USQ
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 18 Feb 2011 04:23
Last Modified: 03 Jul 2013 00:30
Uncontrolled Keywords: road pavements; surface; pavement; pavement construction; road pavement failures; road pavement damage; moving surface loads
Fields of Research (FOR2008): 09 Engineering > 0905 Civil Engineering > 090502 Construction Engineering
09 Engineering > 0905 Civil Engineering > 090507 Transport Engineering
URI: http://eprints.usq.edu.au/id/eprint/18380

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