Effects of pozzolans on acid resistance of shotcrete for sewer tunnel rehabilitation
Bibliographic record
Abstract
This study aims to investigate the use of pozzolans–fly ash (FA), metakaolin (MK), and silica fume (SF)—which can be sourced from local mine waste to improve acid resistance of rehabilitation shotcrete. Cement was replaced with these pozzolanic materials at ratios of 5%, 10%, 20%, and 30% to prepare cylindrical samples. These samples were immersed in sulfuric acids (H2SO4) with various pH for 3 months. Then the mass change and uniaxial compressive strength (UCS) at various immersion ages were monitored as possible indicators of degradation. It was found that FA and SF mixes demonstrated reasonable improvement on acid resistance; of the 13 mixes, 5% SF replacement exhibited the least mass loss after 3 months of immersion. However, optimal percentages with the least UCS change varied depending on the acidity of the immersing acid. Furthermore, the effectiveness of mass change and UCS change was discussed regarding the evaluation of acid resistance.
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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 | 0.000 | 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) | 0.001 | 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".