Valorization of phosphate mine waste rock as alternative aggregates for high-performance concrete
Bibliographic record
Abstract
Natural aggregate quarrying significantly impacts the environment while phosphate mine waste rock (PMWR) offers alternative aggregates for use in high-added value construction materials. This study was the first to investigate the application of three aggregate types from PMWR as a complete substitute to natural aggregate to produce high-performance concrete (HPC). For this aim, three coarse aggregate (CA) types: Flint (F), Phosflint (PF), and Dolomite (D) from PMWR in Morocco were selected and compared with a natural Reference CA (R). Two mixtures were tested: HPC-0.40 and HPC-0.36 with a w/c ratio equal to 0.40 and 0.36. D-HPC and PF-HPC achieved a slump exceeding 20 cm and a 28-d compressive strength (CS) equal to 55 MPa ± 5 MPa on average, similar to the R-HPC, while F-HPC did not meet the requirement for HPC (i.e. a 28-d CS superior to 55 MPa). Scanning electron microscope observations showed that D-HPC exhibited a very dense and indistinguishable interfacial transition zone (ITZ), while F-HPC showed a debonding of F-CA and a larger ITZ size which explain its lower CS. Life ycle assessment revealed a major positive environmental impact on ecosystem quality that reduced land occupation and land transformation by up to 32 %. A secondary evaluation of the valorization of PMWR as alternative fine aggregate (FA) in high-strength mortar (HSM) was investigated and showed that the 28-d CS is equal to 93 MPa for PF-HSM and equal to 81 MPa for D-HSM, superior to RS-HSM which is equal to 61 MPa. Dolomite and Phosflint FA offered a better alternative to natural River sand to overcome the ceiling effect. These findings encourage the construction sector to adopt a sustainable consumption of aggregates by using PMWR as alternative CAs and FAs to produce high-strength construction materials.
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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 | 0.000 | 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) | 0.000 | 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".