Evaluation of geocomposite reinforced pavement for suitability in Queensland roads

Schneekloth, Jenelle (2022) Evaluation of geocomposite reinforced pavement for suitability in Queensland roads. [USQ Project]

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The state of a country’s road infrastructure is directly related to the economic and social success of that country. Road infrastructure costs a considerable amount of money to construct and maintain. When subgrade soils are weak and expansive the cost of constructing a road increases as thick granular layers are required to mitigate the effects of the foundation strata.

Geosynthetic manufacturers invented a product in the 1970’s which claims to be able to reduce granular layer thickness of pavement by up to 30%. Much research has been carried out on this topic with the general agreeance that the inclusion of such products is a viable option in flexible pavement structures, however, a conclusive determination of the optimum placement of geocomposites in flexible pavements has not been made. Therefore, there is a requirement to investigate the effectiveness of geocomposites as pavement reinforcement in unbound flexible pavement structures under traffic loading conditions constructed with materials indigenous to Queensland, Australia. A research project was undertaken to further enhance the knowledge of geocomposite-reinforced roads, as discussed below.

Firstly, a trial pavement was designed and constructed in accordance with relevant specifications and guidelines applicable to Queensland Road authorities. This was done by taking an already existing road that was to be constructed and manipulating the design to include geocomposite reinforcing. The reinforced sections had 25% less granular material when compared to the original design. The construction of the trial was unremarkable as most road construction companies are familiar with geocomposites and have the knowledge and tools to assist in installation of the product.

A series of Falling Weight Deflectometer (FWD) and Light Weight Falling Deflecometer (LWFD) testing was carried out at subgrade level and finish surface level of the pavement. The FWD testing was the most beneficial test for this trial as the data could be used to comprehensively analyse the deflection bowl and the estimated modulus of the pavement layers could be obtained using back analysis software. It was found that the geocomposite reinforcing strengthened the base layer equal to that of the original design when results from the deflection ratio were compared. Furthermore, the back analysis results showed that the geocomposite increase the estimated modulus of the base layer when the reinforcing was placed between 125mm – 250mm below the finish surface level of the pavement. The LWFD testing was able to capture the overall performance of the pavement and did replicate the trend seen in the FWD results, however, the data was not as comprehensive which limited the evaluation of the findings captured by this apparatus.

This research compliments the findings of previous research. The FWD analysis has demonstrated that there is merit to the claim of being able to reduce granular pavement layer thicknesses as the geocomposite appears to stiffen the base course layer. However, some questionable results were Evaluation of geocomposite reinforced pavement for suitablility on Queensland Roads discovered in the FWD testing carried out on the unreinforced control section that shares the same pavement thickness. It is, therefore, important to monitor the long-term performance of the trial, when exposed to normal traffic loading conditions, to further quantify the suitability of geocomposite reinforced pavements in Queensland.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Current – Faculty of Health, Engineering and Sciences - School of Engineering (1 Jan 2022 -)
Supervisors: Manalo, Allan
Qualification: Bachelor of Engineering (Civil)
Date Deposited: 19 Jun 2023 23:36
Last Modified: 20 Jun 2023 01:16
Uncontrolled Keywords: road infrastructure; geocomposites
URI: https://sear.unisq.edu.au/id/eprint/51887

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