A New Supplementary Binder in Foamed Bitumen Stabilisation

Coonan, Tom (2022) A New Supplementary Binder in Foamed Bitumen Stabilisation. [USQ Project]

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Roads are often considered to be an integral role in the social and economic growth of a country. Cold In-Place Recycling (CIPR) with Foamed Bitumen (FB) stabilisation is increasingly becoming the preferred technique for rehabilitation and maintenance of roads across Australia, particularly in Queensland. CIPR recycles materials in the existing pavement (Reclaimed Aggregate Pavement (RAP)) and strengthens the layer by supplying suitable binders to it. Although lime is the preferred supplementary binder for foamed bitumen, there are some drawbacks regarding its use in hot climates as well as some health and safety issues.

Studies were conducted to address these drawbacks using a geopolymer with sodium silicate and fly-ash as the supplementary binder. However, it was found that the FA-Geopolymer was unsuccessful in achieving the minimum design value at 4% of foamed binder content using Class 170 (C170) bitumen as the primary binder. As a result of these findings, this dissertation presents the use of a slightly harder grade of primary binder (Class 320) to determine if the mechanical strength of the geopolymer mix is improved. Numerous laboratory strength tests were performed to allow for a greater understanding of the effect of the C320 bitumen.

Results from the strength testing showed that in all cases, the resilient modulus values for the C320 specimens are lower than that of the previously tested C170 specimens. It was found that C320 specimens had higher density compared to the previously completed C170 specimens. Therefore, a microstructural analysis was completed, and it was determined that poor binder distribution caused the lower resilient modulus values between the different classes of bitumen due to the higher viscosity of the C320 bitumen. The results of this project will lead to a better understanding of the use of C320 bitumen as a primary binder in FB stabilisation with a geopolymer as the supplementary binder. It also has the potential to provide a low risk and a long-term solution for fly-ash which is abundantly available in Australia, and which is desperately in need of utilisation.

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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: Nataatmadja, Andreas
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 20 Jun 2023 22:47
Last Modified: 20 Jun 2023 22:47
Uncontrolled Keywords: road maintenance and rehabilitation; Foamed Bitumen (FB) stabilisation
URI: https://sear.unisq.edu.au/id/eprint/51908

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