The presence of ettringite in concrete affected by alkali‐silica reaction and its potential use as recycled aggregate
Bibliographic record
Abstract
Samples were collected from a 20-year-old concrete suffering alkali-silica reaction for examination using scanning electron microscopy. The concrete was also exposed to cycles of freezing and thawing in service. The old concrete was processed and used as recycled concrete aggregate in new concrete tested under lab conditions. The study shows that backscattered electron imaging, energy dispersive x-ray analysis and x-ray mapping are helpful tools to identify the presence of alkali-silica reaction products. X-ray mapping was found helpful to confirm the presence of reaction products in cases where the products or the cracking are not very clear in the collected image. The study shows the presence of ettringite in the air voids of the concrete. The formed ettringite is believed to have no direct effect on the expansion due to the alkali-silica reaction as they form in an empty space without causing swelling pressure on the concrete. The effect of the ettringite formed in the air voids on the resistance to freezing/thawing was not confirmed in this study. Recycling the old affected concrete as aggregate in new concrete was found to cause significant expansion under lab conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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) | 0.000 | 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 teacher head, 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".