Bibliographic record
Abstract
SUMMARY Action Plan 2000 on Climate Change - Mineral and Metals - Supplementary Cementing Materials (SCMs) is a program with the objective to increase the use of SCMs in concrete production, thus contributing to the reduction of the “CO2 signature” associated with the production of every cubic metre of concrete. The first step taken by the program is the determination of the current situation of SCMs in Canada namely, production, cost, availability, and current usage and areas of high potential for expanded usage of SCMs in Canada including local barriers as well as guidelines and specifications. This exercise should then lead to an identification of a strategy to increase the use of SCMs in Canada. The data gathered on the current situation of SCMs in Canada have shown that around 524,000, 347,000, and 37,000 tonnes of fly ash, Ground Granulated Blast Furnace Slag (GGBFS) and silica fume were used in cement and concrete applications in 2001, which represent 11, 90, and 185% of the quantity produced, respectively. For GGBFS, the remaining 10% of the quantity produced was used in the USA, and for silica fume, 17,000 tonnes were imported from the USA and Norway to meet market demand. Fly ash appears to be the only material that is underused and that represents a potential for increased use of SCMs in Canada. For the GGBFS, the quantity produced can be increased if the demand increases. However, this investigation has shown that there are policy, technical and economic barriers to the increased use of SCMs in Canada. Policy barriers: although these materials have been in the Canadian market for 20 to 30 years, and many projects, including high-profile projects such as Hibernia and the Confederation Bridge, have successfully used high volumes of fly ash and slag, there are still municipalities and provincial agencies that ban or limit the use of fly ash and slag to a certain percentage of replacement for some applications. Technical barriers: the slower setting times and strength development of concrete incorporating fly ash and slag are limiting the use of these materials in applications that need fast form-work removal. The reduced resistance of these concrete mixtures to the freezing and thawing cycles in the presence of de-icing chemicals is also considered a hurdle. The quality of the fly ash, which is related to the type of coal used for the production of electricity in the thermal power plants, is a concern in the Eastern part of the country.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.003 | 0.007 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.014 | 0.001 |
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".