The Durability of Concrete Produced Using CO2 as an Admixture
Bibliographic record
Abstract
Carbon dioxide has been investigated as a beneficial admixture to freshly mixing concrete.The reaction between the CO2 and the hydrating cement forms finely distributed calcium carbonate reaction products.The carbon dioxide can be incorporated into conventional ready mixed concrete production through a simple gas system retrofit.A comprehensive durability evaluation of carbon dioxide treated concrete was conducted.The effect of the carbon dioxide in the fresh state was assessed in terms of slump, air content, plastic density, heat of hydration and time of time.Hardened state tests included compressive strength, freeze-thaw durability (ASTM C666), linear shrinkage, rapid chloride permeability (ASTM C1202), and deicer salt scaling.Comparisons were made between a reference concrete batch, a batch that contained a conventional accelerating admixture, and a batch subjected to the carbon dioxide addition.The concrete to carbon dioxide was found to reduce the time to initial and final set by over 20%.The CO2treated concrete had a 14% higher compressive strength than the control at one day and 10% higher strength at 3 days.Later strengths were equivalent.Durability was general unchanged although salt scaling was reduced.The carbon dioxide could be a viable non-chloride accelerator.
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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 | 0.001 |
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".