Compaction and compressibility characteristics of snail shell ash and granulated blast furnace slag stabilized local bentonite for baseliner of landfill
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View abstract on PubMed
Summary
This summary is machine-generated.Snail shell ash (SSA) and ground-granulated blast-furnace slag (GBFS) effectively stabilize bentonite for landfill liners. The 15% SSA mixture showed superior mechanical strength and low hydraulic conductivity, making it ideal for landfill applications.
Area Of Science
- Geotechnical Engineering
- Materials Science
- Environmental Engineering
Background
- Bentonite is a common material for landfill liners due to its low permeability.
- Stabilization of bentonite with industrial by-products like SSA and GBFS can enhance its engineering properties.
- Snail shell ash (SSA) is rich in CaO, and ground-granulated blast-furnace slag (GBFS) is rich in SiO2, suggesting potential for pozzolanic reactions.
Purpose Of The Study
- To investigate the effects of SSA and GBFS on the compaction and compressibility of local bentonite.
- To evaluate the mechanical properties (unconfined compressive strength, shear strength, elastic modulus) and hydraulic conductivity of treated bentonite.
- To determine the optimal mixture of SSA and GBFS for enhancing bentonite's suitability as a landfill base liner.
Main Methods
- Compaction tests (Proctor test) to determine maximum dry density and optimum moisture content.
- Unconfined compressive strength (UCS) tests, shear strength tests, and elastic modulus measurements.
- Hydraulic conductivity tests (permeability tests) conducted in triplicate.
- Scanning Electron Microscopy (SEM) for microstructural analysis.
Main Results
- Untreated bentonite had optimal compaction at 32% moisture content and 1423 kg/m³ dry density.
- The mixture of 20% GBFS and 5% SSA achieved the highest dry density (1561 kg/m³) and lowest optimum moisture content (13%).
- The 15% SSA-treated sample exhibited the highest unconfined compressive strength (272.61 kPa at 28 days), shear strength (49 kPa), elastic modulus (142 MPa), and favorable hydraulic conductivity (5.57 × 10⁻⁸ cm/s).
- Treated samples showed reduced compressibility compared to the control.
Conclusions
- The 15% SSA mixture demonstrated significantly improved mechanical properties and hydraulic conductivity, outperforming other mixtures and the control.
- SSA and GBFS effectively stabilize bentonite, enhancing its performance for landfill base liner applications.
- The microstructural changes observed via SEM in the 15% SSA mixture support its potential as an effective landfill liner material.
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