Renewal of Potable Water Systems Using Cement Mortar Lining; an Investigation into Corrosion Reduction and Water-loss Prevention
Bibliographic record
Abstract
Many Canadian cities are faced with the problem of an aging and deteriorating iron water distribution network - pipe breaks, leakage, and/or aesthetic water quality problems. Public confidence in municipalities’ ability to deliver safe, clean drinking water to customers has been eroded, especially in areas of water distribution networks receiving coloured water events that result from the internal corrosion of aging iron watermains. Cement mortar lining is one of the most widely used non-structural watermain rehabilitation methods for the prevention of coloured water events due to internal iron pipe corrosion; however, it is also thought/claimed to be a means of controlling corrosion pin-hole leakage. \n \nThis thesis presents the results of a laboratory testing program designed to investigate the renewal of potable watermains via the use of cement mortar lining. The specific focus of this thesis is the ability of the cement mortar lining to bridge corrosion pin-holes and prevent water loss from the watermain, and the effects of mortar application on the corrosion protection provided to the iron watermain by cement mortar lining. The results of this study are based on short term testing and do not consider fatigue. \n \nThe ability to bridge corrosion pin-holes / water loss prevention laboratory testing program found that pressure should not be returned to a newly lined watermain until the lining has cured for a period of at least four days to prevent failures from occurring prior to the lining achieving sufficient strength characteristics if the lining is to be used as a structural rehabilitation technique. The cure time corrected normalized thickness at failure data was found to be a Gumbel distributed data set. The Gumbel distribution can be used to predict the lining thickness required to bridge a known corrosion pin-hole diameter with a set degree of confidence that failure will not occur. A 3 mm thick cement mortar lining can bridge a pin-hole 12.0 mm in diameter while a 5mm thick cement mortar lining can bridge a pin-hole 19.9 mm in diameter with a 95% probability that failure will not occur \n \nThrough the corrosion prevention testing program it was determined that the thickness of the cement mortar lining does not affect the ability of the lining to prevent corrosion from occurring. This was determined for cast iron pipes which have been lined for a period of one year. It is recommended that corrosion potential testing be performed on cement mortar lined watermains that have been in service for a longer period of time to determine if this consistent over the life cycle of the cement mortar lined watermain.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".