Comparison of Polyphosphoric Acid-Modified Asphalt Binders with Straight and Polymer-Modified Materials
Bibliographic record
Abstract
This paper discusses the effects of polyphosphoric acid (PPA) modification on asphalt binders. Findings are compared with those for straight and polymer-modified materials of similar grades. The effect of PPA modification was investigated by means of conventional protocols as well as three new binder tests developed in Ontario, Canada. The compact tension test and the extended bending beam rheometer protocol were used to investigate low-temperature performance properties. The double edge-notched tension test was used to study the resistance to ductile failure. The brittle state fracture properties and the reversible aging processes were largely unaffected by PPA modification. However, changes in the low-temperature grade were considerable in some instances. While the essential work of fracture increases with the addition of PPA, the yield stress increases more rapidly in most binders and thus results in an overall drop in strain tolerance in the ductile state. Recent field experience in Ontario suggests that the use of PPA may either prevent or contribute to wheelpath cracking, depending on the formulation and concurrent use of polymer.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".