Synergistic Effects of Polyphosphoric Acid and Montmorillonite Nanoclay on the Performance Properties of Asphalt Binder
Bibliographic record
Abstract
Montmorillonite nanoclay has been used to improve asphalt binder stiffness, rutting resistance, and oxidation stability, but its moisture-induced swelling limits durability. This study evaluates polyphosphoric acid as a complementary additive to reduce swelling and enhance nanoclay performance. The acid intercalates into clay interlayers, creating a hydrophobic barrier against water ingress. Three binders were tested: neat PG 64 22, nanoclay modified, and a hybrid binder with both nanoclay and polyphosphoric acid. Performance was assessed using PG grading, multiple stress creep recovery, frequency sweep, swelling, and extended bending beam rheometer tests. The hybrid binder reduced swelling by nearly fourfold relative to nanoclay alone and showed improved rutting resistance and aging durability after thermal conditioning. However, both nanoclay and hybrid binders displayed greater physical hardening at low temperatures, indicating a trade-off between high-temperature durability and low-temperature flexibility. Overall, the hybrid system provides enhanced moisture protection and aging resistance while highlighting limitations in cold climates.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.001 | 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".