INTERLABORATORY EVALUATION OF Tg OF AMBIENT-CURED EPOXIES USED IN CIVIL INFRASTRUCTURE
Bibliographic record
Abstract
Ambient-cured epoxies used to bond high strength continuous fibers to concrete for strengthening purposes can have glass transition temperatures (Tg) that are not only close to the service temperature but can also change over time as a function of environmental conditions. While the design ramifications of using such an epoxy resin with an evolving Tg close to the service temperature are unclear and difficult to predict, recommended methods for assigning a Tg for such resins are nonetheless needed. In the present investigation, an interlaboratory evaluation of Tg characteristics of several ambient-cured epoxy resins using dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) was carried out. The need for standardized specimen conditioning prior to Tg measurement is demonstrated. Of the three DMA Tg methods employed, the tan δ method provided the lowest standard deviation. Because of its reliability and its roots in mechanical testing, the DMA tan δ method applied during a single temperature up-ramp is recommended for assigning Tg.
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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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".