Assessing the blending of recycled LDPE flakes with bitumen in mixtures using rheological and thermal properties: a case study
Bibliographic record
Abstract
Despite growing interest in asphalt mixtures modified with low-density polyethylene (LDPE), the industry lacks clear guidelines to reliably produce these materials, particularly with the dry method where the role of melted plastic particles is unclear. This paper assesses the blending potential of recycled LDPE flakes with bitumen introduced by the dry method and develops a methodology to estimate how much plastic functions as a binder modifier. Five mixtures were compared: four laboratory-produced mixtures (0% and 1% LDPE, unaged and short-term aged) and one plant-produced mixture with 1% LDPE. Bitumens were extracted and recovered (E&R) to evaluate LDPE presence through rheological and thermal analyses. The results indicated that most LDPE remained dispersed as fibres/particles with aggregate, but a small fraction systematically modified the binder, notably in plant-produced mixtures. Workability testing further suggested LDPE primarily functions as a mixture modifier rather than as a bitumen modifier in the dry process.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".