Compilation of 5 papers on (1) Electrical resistivity as a durability indicator and (2) Cracking tendency in hardening concrete
Notice bibliographique
Résumé
The report contains 5 papers that were presented at the 2nd Int. symposium on Advances in Concrete through Science and Engineering 11-13 Sept. 2006, Quebec City, Canada (printed in the symposium proceedings RILEM PRO 51, ISBN 2-35158-003-06, Ed. by J.Marchand and B.Bissonnette). The first three papers deal with electrical resistivity as a durability parameter for concrete, while the two last papers deal with cracking tendency of hardening concrete. Electrical resistivity (Paper 1-3): The parameter is very important as a durability indicator since high resistivity is beneficial as it means slow corrosion. Electrical resistivity (ER) has been studied with regard to electrical frequency range, concrete degree of saturation (DS), -temperature, -aging effect and -composition. The total investigation include lab. tests on lab.- made specimens and on field cores, as well as field measurements on long term sea exposed concrete elements using both automatic and manual monitoring systems. The ER (lab.and field tests) of water and atmospherically stored high performance concretes (HPC) increased clearly over time (years) due to aging effects, while sea water exposure (field cores) did not display any clear increase. In the latter condition the positive aging effect is believed to be counteracted by the intrusion of chlorides (more ions - lower ER). For water stored HPC even a small decrease in DS clearly increased the ER (indicating early discontinuity of the capillary water), while for traditional bridge concrete with higher w/b the resistivity was not so affected by DS. In the field measurements, over years, on sea exposed elements a beneficial aging effect was seen. The ER increases, not surprisingly, with concrete quality (especially for w/b-ratios below around 0.40); in the field tests this was particularly the case after longer times. Very high ER values were found for the concretes with fly-ash (both lab. and field), especially at longer times.\n\nCracking tendency in hardening concrete (Paper 4-5): Thermal (TD)- and autogenous (AD) deformations are the primary causes of self-induced stresses in hardening concrete structures subjected to restraint conditions. Much attention has been paid to AD during the last 10-15 years. This is seen, for instance, as the many conferences devoted exclusively to ADaspects. In general, except for super HPC (w/b-ratios below 0.3), it appears that TD is greater than AD and it is therefore surprising that little attention has been paid to the coefficient of thermal expansion (CTE) in recent literature. Paper 4 presents an experimental strategy on how to separate TD and AD in tests and discusses the mechanisms behind the strong moisture dependence of the CTE. Paper 5 shows experimental results from a study on the effect of fly-ash (FA) on crack sensitivity. The given test series shows a beneficial effect of FA when an efficiency factor (k) of 1.0 is used for FA in the effective w/b-ratio calculation. The standards prescribes k=0.4 for FA added during mixing and k=1.0 when FA is part of a certified cement. The paper discusses this issue.
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 | 0,004 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,002 | 0,002 |
| Bibliométrie | 0,010 | 0,009 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,002 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,029 | 0,014 |
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 ».