| Abstract: | Expansive soils occur throughout the world. The annual damage to property has been estimated to be over one billion dollars. The properties of expansive clays have long puzzled the soils engineer. To further the understanding of expansive soils this explanatory research was undertaken using new techniques to investigate the influence of soil suction, clay microstructure and applied external loading upon the swelling behavior. For the soil tested, the microstructure produced by kneading compaction did not change the particle orientation to any significant degree. Evaluation of the microstructure was performed with both X-ray diffraction and scanning electron microscopy techniques. The microstructure is perhaps best described by multi-grain or packet arrangements. A higher degree of packet dispersion occurred at molding water contents wet of optimum, however, it did not approach any high degree of preferred particle orientation. ... |
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