Rheological Properties of Bitumen and Bitumen-Heptane and Bitumen-Heptanol Mixtures
Bibliographic record
Abstract
The rheological changes and high viscosity of bitumen, arising from high molecular weight molecules in bitumen, are the main challenges for its production to the surface and its transportation in pipelines. To solve the environmental issues associated with bitumen recovery, such as greenhouse gas emissions from steam-based recovery processes, solvent injection has been a strong alternative given their ability to reduce the viscosity of bitumen. Among solvent options, the ability of alcohol solvents has not been clearly studied. In this study, two sets of experiments were conducted on the rheology of bitumen and solvent-bitumen mixtures. The first set of experiments demonstrates that the rheological behaviour of bitumen is complex since its viscosity varies with both shear rate and time. In the experiment, the rheology of bitumen and bitumen-heptanol mixtures were examined. Their viscosities and shear stress were measured with increasing and decreasing shear at 24C. The results showed that non-Newtonian behaviour was observed in all samples. Additionally, hysteresis and ramp test of the viscosity profiles revealed that the bitumen and its mixtures are time-dependent (anti-thixotropic) fluids. In the second set of experiments, the viscosity of bitumen in contact with heptanol was examined and compared to bitumen-heptane mixtures. The results show that the effects of heptanol on viscosity reduction were less than that of heptane. The literature values of Hansen Solubility Parameters (HSP) of bitumen, asphaltenes, heptanol and heptane were used to explain the reason for the lower viscosity reduction effect of heptanol on bitumen. The relatively high viscosity of heptanol and deviation of the fractional HSP between bitumen and heptanol is also consistent with the results.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".