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Compacted Anthropogenic Materials as Backfill for Buried Pipes.
Andrzej Głuchowski1,2, Raimondas Šadzevičius2, Rytis Skominas2
1SGGW Water Centre, Warsaw University of Life Sciences-SGGW, 02787 Warsaw, Poland.
Materials (Basel, Switzerland)
|February 6, 2021
Summary
Anthropogenic materials (AM) can substitute natural aggregates in buried pipe backfill, but their soil reaction modulus (E) is generally lower. Careful selection and treatment are needed for effective use of recycled concrete aggregate, crushed brick, recycled asphalt pavement, fly ash, and bottom slag.
Area of Science:
- Geotechnical Engineering
- Civil Engineering Materials Science
Background:
- Buried pipe structural performance depends on backfill material properties and compaction.
- Pipe-soil interaction is crucial for buried pipe integrity.
- Backfill strength is characterized by modulus of soil reaction (E') and constrained modulus (E).
Purpose of the Study:
- To evaluate the constrained modulus (E) of five types of anthropogenic materials (AM) using oedometric tests.
- To compare the performance of AM with natural aggregates (NA) for buried pipe backfill applications.
- To determine the suitability of AM as a substitute for NA.
Main Methods:
- Conducted extensive oedometric tests on five AM types: recycled concrete aggregate (RCA), crushed brick (CB), recycled asphalt pavement (RAP), fly ash and bottom slag mix (FA + BS), and blast furnace slag (BFS).
- Measured the constrained modulus (E) for each AM.
- Compared the measured E values with those of natural aggregates (NA) with similar gradations.
Main Results:
- Anthropogenic materials exhibited different behavior compared to natural aggregates.
- Generally, AM showed lower constrained modulus (E) values than NA for the same gradation.
- Recycled concrete aggregate (RCA) and blast furnace slag (BFS) showed potential for direct substitution.
- Crushed brick (CB) may require special treatment.
- Recycled asphalt pavement (RAP) and fly ash + bottom slag (FA + BS) may require extra compaction efforts.
Conclusions:
- Anthropogenic materials can be viable alternatives to natural aggregates in buried pipe backfill, but their mechanical properties differ.
- Specific AM, like RCA and BFS, can be used directly as substitutes for NA.
- Other AM, such as CB, RAP, and FA + BS, require specific treatments or enhanced compaction to achieve desired performance.
- Understanding the constrained modulus (E) of AM is critical for effective buried pipe design and ensuring adequate pipe-soil interaction.
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