Chemical and Sedimentological Characterization of Moulvibazar Silica Deposit of Bangladesh as Standard Sand
Bibliographic record
Abstract
S tandard sand is used for conducting the compressive strength test of hydraulic cement mortars. American society for testing and materials (AS TM) recommends Ottawa S tandard S and (OS S ). Bangladesh has quiet a rich sand deposits but in the scenario of not having standard sand, OS S is imported from abroad for using in different tests in Bangladesh. In this work, a very strong effort has been made to standardize the sand for Bangladesh using its own available deposits and thus to eliminate the unwanted expenditure of foreign currencies. Hence, we selected the Moulvibazar silica deposit (situated at the piedmont of Dupi Tila formation) with the maximum probability of having high silica content by studying the geological formation of Bangladesh. OS S contains about 99.7% of silica and has 'rounded' shape which enables non-reactivity of sand with cement constituents during the testing of hydraulic cement mortars. XRD analysis of the sand sample shows that it contains about 96.87% of silica after water wash and 91.17% of silica after acid wash. S EM images were used to measure the roundness of the sand samples. The roundness of the water wash and acid (0.1N HCl) wash sand samples (according to Waddle scale) were found to be 0.28 and 0.27 respectively. Both sand samples fall into 'sub-rounded' class of roundness grade (of Pettijohn gradation). An attempt was taken to observe the change of roundness by mechanical abrasion of the sample. It was observed that the roundness was decreased because of the growth of secondary corners. DS C isotherm analysis was carried out at three different temperatures (30 0 , 45 0 and 60 0 C) to investigate the reactivity of sand samples. Neglecting the unaffected reactivity, instead, considering the high silica content and subrounded shape of the sample, the sand of Moulvibazar deposit could be recommended for using as standard sand for testing hydraulic cement mortars.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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) | 0.002 | 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".