Another Look at the Bending Beam Rheometer for Specification Grading of Asphalt Cements
Bibliographic record
Abstract
This paper describes how the bending beam rheometer (BBR) protocol was adapted for specification grading in the early 1990s, and experience to date has shown that asphalt cements of the exact same grade can perform very differently. Hence, the authors efforts have focused on investigating which changes in the method can improve consistency. Recovered asphalt cements from 20 Ontario pavements with large performance variations were tested at –10oC, –20oC, and –30oC after various periods of conditioning. Samples were loaded for the regular 240 s, followed by unloading for 720 s, allowing the elastic and viscous deformations to be separated. The regular specification parameters, stiffness (S) and relaxation ability (m-value) were determined, in addition to a range of other performance-related properties. It was found that the confounding effect of simultaneous elastic and viscous deformations and inadequate conditioning prior to testing in the BBR protocol are the most important reasons for the observed inconsistency.
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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 | 0.006 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".