Effect of fly ash replacement on alkali and sulphate resistance of mortars
Bibliographic record
Abstract
The use of fly ash as a supplementary cementing material in concrete and mortar has dramatically increased in recent years due to its improvement of concrete and mortar properties and its environmentally friendly impact. In this thesis, the sulfate resistance and alkali-silica reaction in mortars containing 0, 20, 40, 60, and 80% fly ash replacement levels were investigated to determine the effect of fly ash content on durability. Four types of cement and two types of fly ash were used in the tests, the cements used were of different alkali contents and with and without blended silica fume. The fly ashes consisted of medium and high calcium contents. The results showed that the expansion resulting from sulfate attack as well as the alkali-silica reaction considerably decreased with the increase of fly ash content, but the strength of the mortar samples greatly decreased as well. The effectiveness of fly ash in both tests was highly dependent on their CaO content and on the chemistry of cements utilized. 20% Sundance fly ash replacement was sufficient to maintain the sulfate expansion after six months of exposure below CSA allowable expansion limit of 0.05% for high sulfate resistance cement and also below the Canadian limit of 0.1% in the ASR test. For Rockport fly ash, replacement levels at 40% were needed to maintain the expansion below the limit of 0.1% in ASR and sulfate test. The presence of silica fume blends significantly reduced the expansion due to alkali-silica reaction and sulfate attack; addition of fly ash to silica fume blended cements did not significantly improve performance.
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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".