The Effect of Alkali-Silica Reaction on Aggregate Interlock In Reinforced Concrete and the Use of Digital Image Correlation to Monitor the Long-Term Behaviour of Concrete Structures
Notice bibliographique
Résumé
Alkali-silica reaction (ASR) is a chemical reaction between the alkali hydroxides from the concrete pore solution and some siliceous mineral phases present in the aggregates used to make concrete. ASR generates a secondary product, the so-called ASR-gel, that swells upon moisture uptake, leading to induced expansion, microcracking, and reduction in the mechanical properties of the affected material. ASR is likely the most harmful damage mechanism affecting the serviceability and long-term performance of concrete infrastructure worldwide, yet its structural implications in concrete structures remain unclear. Even though shear resistance of reinforced concrete has been studied extensively by the research community due to the brittleness and danger associated with concrete shear failures, knowledge on the impact of ASR on reinforced concrete shear resistance is very limited. To fill this lack of knowledge, the effect of ASR on the aggregate interlock shear transfer mechanism in reinforced concrete was investigated. Lightly reinforced shear push-off specimens with low to moderate expansion levels were tested while recording crack kinematics. The experimental testing program allowed to decouple the deleterious effect of ASR microcracks within the reactive coarse aggregate particles and the beneficial effect of the so-called chemical prestressing. The aggregate interlock shear strength was significantly impacted, even in the case of a low expansion level for which the microcracks have theoretically not reached the cement paste yet, and surprisingly, it was not affected by prestressing. The experimental results were compared to predictions from three existing simplified aggregate interlock models which tended to overestimate the measured shear strengths. Digital image correlation (DIC) is an innovative optical measurement technique that could provide several advantages for long-term structural inspections such as remote full-field measurements. A method was proposed to correct 2D-DIC measurement errors associated with the inevitable camera movement between photographs taken during different inspections. Using the aforementioned push-off specimens, it was applied to the monitoring of shear crack kinematics and ASR expansion. The method significantly improved measurements produced from images acquired with a non-expensive hand-positioned camera equipped with a lens of normal focal length and a free to use DIC software. For ASR expansion monitoring, the measurement errors could not be reduced below a selected tolerance limit of ±0.02 mm (±0.01% strain), although increasing the measurement gauge length could potentially provide satisfactory results. On the other hand, over 99 and 96% of the measurements were within the selected tolerance limit of ±0.1 mm for the corrected crack width and slip measurements, respectively. These promising results validate the potential of the proposed method to overcome errors associated with camera movement between photographs and as such, it represents a step towards the use of the DIC technique for periodic structural inspections.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 tête enseignante, 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 ».