- Title
- Investigation of the interaction between truck tyre waste rubber particulate and penetration grade and polymer modified bituminous binders
- Creator
- Mgangato, Siseko
- Subject
- Truck equipment industry
- Date Issued
- 2020
- Date
- 2020
- Type
- Thesis
- Type
- Masters
- Type
- MTech
- Identifier
- http://hdl.handle.net/10948/48500
- Identifier
- vital:40882
- Description
- Recent studies have investigated the waste tyre crumb rubber (TCR)-bitumen interaction by observing the swelling of waste TCR at elevated temperatures. It was found that the waste TCR-bitumen interaction alters the rigidity and shape of TCR, which causes the failure of asphalt mixtures. Consequently, the problem occurs when the waste TCR swells during waste TCR-bitumen interaction from mixing and transportation of the asphalt mixture. Extensive laboratory studies have shown that the rate of absorption of bitumen is correlated with the TCR rubber composition and particle size. However, it is possible that swelling of waste TCR can be prevented or reduced before waste TCR-bitumen interaction by means of pre-treating the rubber crumb as to prevent the alteration of bitumen properties. Therefore, this study seeks to investigate the interaction of truck tyre wastes rubber particulates (WRP)-bitumen with the pretreatment of truck tyre WRP with H2SO4, HNO3 and HCℓ. This treatment was done to make TCR suitable for the dry process asphalt mixtures, where TCR acts as a filler instead of altering bitumen binder properties. The investigation characterized truck tyre WRP-bituminous binder interaction by interacting a single truck tyre WRP with penetration grade (50/70 and 70/100) and industrial polymer modified binders (AE-2 and PolyMod). The interaction through kinetic study revealed that the swelling of truck tyre WRP is either a non-Fickian two-step swelling or anomalous diffusion mechanism of bituminous binders. In addition, the study showed that temperature has an effect on the diffusion, sorption and permeation coefficients; where coefficients increased as the temperature was increased. The characterization of which bituminous binder component was observed by the truck tyre WRP was studied using Fourier Transform Infra-Red Spectroscopy (FTIR), Carbon 13 Nuclear Magnetic Spectroscopy (13C NMR) and Thermalgravimetric Analysis (TGA). The study showed that by analysing the extracted bituminous binder from residual truck tyre WRP after the interaction, Polycyclic Aromatic Hydrocarbons (PAHs) consisting of molecular structure characteristics of bitumen constituent aromatics. So as to restricting the diffusion of bituminous binder into truck tyre WRP, the surface of truck tyre WRP was treated with H2SO4, HNO3 and HCℓ acids from concentrations of 1, 6 and 12 M. The H2SO4 and HCℓ treated WRP showed a change in molecular ii structure, toluene sorption coefficient, surface morphology and thermal characteristics (TGA and DSC). However, changes that were observed with the HNO3 treatment showed that the truck tyre WRP material was in fact being digested by the HNO3 acid. In all the respective acid treatments, the effects were distinct with 12 M acid concentration. This was observed with a decrease in toluene sorption coefficient with increasing acid concentration. From the treatment of the truck tyre WRP with H2SO4, HNO3 and HCℓ acids, the 6 M acid concentration showed desirable characteristics. Interaction of the respective acid treated truck tyre WRP-bituminous binder interaction was carried out following the drainage basket method. In this investigation, the 6 M acid (H2SO4, HNO3 and HCℓ) treated WRP was used and it was found that swelling followed a two-stage and anomalous non-Fickian diffusion patterns. Hence HNO3 absorbed the least binders and this was confirmed by the low sorption coefficients. Although the H2SO4 and HCℓ did not show a significant difference with 50/70 and 70/100 and a significant change with AE-2 and PolyMod binder absorption, the dynamic shear rheometre (DSR) measurements revealed that the residual binders (50/70, 70/100, AE2 and PolyMod) had a higher rutting temperature than respective original binder, where G*/sinδ is ≤ 1 kPa. These binders also had lower fatigue to cracking temperature through analysis of G*sinδ at 5 000 kPa. In addition, the measured phase angle at the respective rutting temperature showed to be between 45 ̊and 90 ̊which suggested that the binders were viscoelastic. Viscoelastic characteristics were therefore assessed using multiple stress creep recovery test (MSCR). The measured MSCR parameters, % recovery and non-recoverable compliance, showed that there was a slight gain in elasticity with 50/70 and 70/100 after the interaction. The AE-2 and PolyMod binders experienced a decrease in elasticity after the interaction. Despite unforeseen outcomes, the treatment of truck tyre WRP with H2SO4, HNO3 and HCℓ acids decreased the swelling phenomenon of truck tyre WRP in a bituminous binder.
- Format
- Xv, 179 leaves
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
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Collections
NMU School of BioMolecular and Chemical Sciences
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Mganato, S 210110317 Dissertation April 2020.pdf | 7 MB | Adobe Acrobat PDF | View Details Download |