Parameters influencing pressure during pumping of self-compacting concrete
Bibliographic record
Abstract
The main difference between conventional vibrated concrete (CVC) and self-compacting concrete (SCC) is observed in the fresh state, as SCC has a significantly lower yield stress. On the other hand, the placement of SCC by means of pumping is done with the same equipment and following the same practical guidelines developed for CVC. It can be questioned whether the flow behaviour in pipes of SCC is different and whether the developed practical guidelines can still be applied. This paper describes the results of full-scale pumping tests carried out on several SCC mixtures. It shows primarily that the slump or yield stress of the concrete is no longer a dominating factor for SCC, as it is for CVC. Instead, the pressure losses are well related to the viscosity and the V-funnel flow time of SCC. Secondly, bends cause an additional pressure loss for SCC, which is in contrast to the observations of Kaplan and Chapdelaine and the estimation of the practical guidelines is not always on the safe side. Finally, due to the specific mix design of SCC, blocking is less likely to occur during pumping operations, but the same rules as for CVC must be applied during start-up.
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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 | 0.001 |
| 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 | 0.001 | 0.001 |
| 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".