Polyphosphoric Acid–Modified Binders and Mixtures: Aggregate and Binder Interactions, Rutting, and Moisture Sensitivity of Mixtures
Notice bibliographique
Résumé
Polyphosphoric acid (PPA) has been increasingly used as a means of producing modified binders for the past 10 to 15 years in North America. Reports of isolated or regional use of phosphoric acid and PPA prior to the advent of Superpave performance grade (PG) binders have been published, but the increased demand for high-performance binders resulting from the adoption of PG binders stimulated more widespread research into the means by which PPA could effectively and economically enable binder suppliers to meet these demands. Consequently asphalt suppliers in all regions of the United States and Canada turned to PPA to meet the new specifications. It was found that PPA, when used at levels as low as 0.5% by weight of binder, could increase the high-temperature PG of some binders by one full grade. Most binders required approximately 0.8% to 1.2% PPA by weight of binder and some required considerably more; sometimes more than 2%. Still other asphalt suppliers found that the addition of low levels, typically less than 0.5% by weight, of PPA to polymer-modified binders enabled them to reduce polymer loading without negatively impacting mixture performance and in some reported cases enhancing mixture performance. Almost simultaneously with the onset of PPA usage, concerns were raised by a cross section of individuals, organizations, and agencies associated with the asphalt production and supply, bituminous paving and governmental sectors. These concerns were manifested by fears of mixture stripping because of the hygroscopic nature of PPA and fears of accelerated aging and adverse effects on low-temperature properties of both binders and their mixtures because of the well-known use of phosphoric acids, PPA, and phosphorus pentoxide to catalyze the production of roofing asphalt during the blowing process. There was also the often unstated but ever-present belief that purchasers of PPA-modified binders were being cheated because they were not receiving polymer when purchasing some premium PG grades. Some of these concerns were justified, many were not. The information in this study endeavors to put some perspective around these concerns, to show where there might be cause for concern and where there is not. This document does not provide an answer to all questions and it raises a few questions that still need to be answered.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».