Characterization, rheology and microstructure of laponite suspensions
Bibliographic record
Abstract
The research presented in this thesis is part of a broader ongoing effort aimed at validating at the laboratory scale the use of laponite suspensions for treating liquefiable soils, as an alternative to sodium pyro-phosphate treated bentonite suspensions. The specific objectives of the work were: (a) the characterization of laponite—a material new to the geotechnical community, (b) a study of the rheology of concentrated laponite-water suspensions, and (c) an investigation into differences in cyclic triaxial behavior observed between dry-mixed and permeated specimens. Through the work performed new insights were also gained into the microstructure of laponite suspensions. Characterization of laponite relied on a number of techniques including TEM, TGA, XRD and sorption/desorption tests. Rheological measurements on the laponite-water suspensions were conducted using a Physica MCR 301 Rheometer. Falling head tests were performed to measure the hydraulic conductivity of Ottawa sand-laponite specimens. Microstructural observations on both the suspensions and the sand-laponite specimens were conducted employing cryo-SEM. Based on rheological measurements, laponite appears to be a viable material for treating liquefiable soils: a 3% suspension exhibits Newtonian behavior over a time window of a few hours, indicating that injection may be practical in the field; once delivered into the sand matrix, within a few hours, the suspension develops a gel structure with properties that in the case of bentonite have been associated with mitigation or elimination of liquefaction. Cryo-SEM observations indicate that the gel microstructure is formed by elongated cells with the longest dimension over three orders of magnitude greater than the 25–50 nm size of the laponite particles. Increased ionic strength (10−4 M NaCl–1 M NaCl), results in more densely packed walls. These observations are consistent with changes in the rheological behavior, and raise questions about existing phase diagrams for this material. Hydraulic conductivity measurements and cryo-SEM observations highlight differences between sand-laponite specimens prepared through dry-mixing and permeation. In the first, the gel in the sand pores appears denser and more concentrated in proximity to the particle contacts, and higher values of k are measured.
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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".