Effect of Heat Treatment of the Clayey Soils on the shear strength with use of sodium silicate

다국어 초록 (Multilingual Abstract)

The two type of clayey soils activated thermally at 500℃ for 15 and 60 minutes (as the residual time) were mixed with sodium silicate(Na_2SiO_3) at a concentration of five percent by weight of the sample. The mixture was compacted with pressure to form the cylindrical specimens. After 7 days room curing, these sample were subjected to a triaxial strength. The composition of the reaction products with Na_2SiO_3 were examined by X-Ray Diffraction(XRD) and Scanning Electron Microscopy(SEM)
The results indicated that the clayey soils activated thermally for 60 minutes had greater strength and more extensive formation of crystalline reaction products than that of 15 minutes. The resultant crystalline products appear to be polymorphic varieties of zeolite minerals, which constitute a complex of Na-Al-Si-Fe-Ca-Mg, but contained as appreciable amount of iron ions in their structure. Substitution of Fe^+++ for Al^+++ his suggested due to the thermal weakening of the alumina-silica structural bond of clay lattice.

목차 (Table of Contents)

• 1. Introduction
• 2. Experiments
• 2.1 Raw Materials
• 2.2 Heat Treatment
• 2.3 Sample Preparation
• 2.3 Tests
• 3. Results and Discussion
• 3.1 XRD
• 3.1.1 Primary Heat-Treated Clays(PHC).
• 3.1.2 Secondary Heat-Treated Clay(SHC)
• 3.2 SEM
• 3.2.1 Primary Heat-treated Soil(PHS)
• 3.2.2 Secondary heat-treated soil (SHS)
• 3.3 Shear strength
• 3.3.1 KC soil
• 3.3.2 SC Soil
• 4. Conclusion