A Comprehensive Investigation on Microscale Properties and Macroscopic Behavior of Natural Expansive Soils

Understanding the complicated behavior of expansive soil requires in-depth exploration of microscopic phenomena under varying situations, especially when the soil stays unsaturated and experiences swell-shrink cycles. This study is dedicated to a comprehensive investigation of eleven micro-scale properties that function as revealing factors of these electro-physico-chemical mechanisms and the associated surface forces. These microscale properties include: specific surface area (Sa), cation exchange capacity (CEC), surface conductance (λddl), soil acidity (pH), mineralogy (from X-ray diffraction), structure (from scanning electron microscopy), elemental composition (from energy-dispersive X-ray spectrometry), diffuse double layer thickness (t), real relative permittivity (κ'), effective conductivity (σ) and suction (s). Four naturally collected and two laboratory stabilized expansive soils were selected as the study objects. The roles of some microscale properties in determining the macroscopic behavior of volume change and shear strength have been thoroughly examined through experimental work including three dimensional water content-volume-suction studies and a triaxial test program on unsaturated specimens along three capillary paths. The effects of chemical stabilization by fly ash have also been extensively evaluated from a microscopic point of view.

Author dc:creator

• Lin, Botao

Advisor dc:contributor.advisor

• Cerato, Amy B

• Swelling soils
• Soil physics
• Environmental chemistry

Language dc:language

en_US

Identifier

99318234002042

OAI record oai:identifier

https://shareok.org/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ashareok.org%3A11244%2F319087