Microbiological induced carbonate (CaCO3) precipitation using clay phyllites to replace chemical stabilizers (cement or lime)
| Autor: | Eduardo Garzón Garzón, Enrique Romero, Laura Morales, Pedro José Sánchez-Soto |
|---|---|
| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. MSR - Mecànica del Sòls i de les Roques |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Clay soils--Stability Compaction energy Compaction 020101 civil engineering Water retention 02 engineering and technology engineering.material Permeability 0201 civil engineering chemistry.chemical_compound Breakage Geochemistry and Petrology Specific surface area Sòls argilosos -- Estabilitat Lime Cement Clay phyllites Porosimetry MICP Compressibility Geology 021001 nanoscience & nanotechnology Calcium carbonate chemistry Chemical engineering engineering Carbonate Enginyeria civil::Geotècnia::Mecànica de sòls [Àrees temàtiques de la UPC] 0210 nano-technology |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| ISSN: | 0169-1317 |
| DOI: | 10.1016/j.clay.2019.03.018 |
| Popis: | The objective of the present study is to develop a biotechnological tool for a new application of clay phyllites as stabilized materials in linear works replacing chemical stabilizer (e.g. cement or lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of the Bacillaceae family (Bacillus pasteurii). Part of the development process conducting a chemical and mineralogical characterization and an examination of physical and hydromechanical properties. The results of this study show that the effect of bacteria on clay phyllites increases the calcium carbonate content, specific surface area and plasticity values. These increased values are caused by the addition of a non-plastic component to clay phyllites resulting in a more aggregated structure through the precipitation of calcium carbonate from the bacteria, ultimately filling the pores of this material. Microbiological treatments on clay phyllites tends to aggregate the original particles, creating aggregates that are partially associated with the formation of calcium carbonate. Said process is influenced by the curing and compaction procedures conducted on samples, which also cause breakage of carbonated structures formed during treatment. As a result of this breaking process of aggregates, some compaction energy is lost and the treated samples do not reach the maximum dry density of the natural state for the same level of compaction energy applied. Treated samples display a slightly larger friction angle with no cohesion, consistent with filling properties and denser condition. Compressibility is consistently lower than that of the natural state. Comparison of collapse data shows that the occurrence and amount of collapse are controlled by the as-compacted dry density. It is also determined that higher compaction effort is even more effective than increasing the amount of bacteria introduced to stabilize the sample for the filling of pores (size ranges 3–50¿µm) with calcium carbonate. However, the post-ageing compaction destroys the initial binding/cementation effect. |
| Databáze: | OpenAIRE |
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