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| INFLUENCE OF MODIFIERS ON DISPERSITY AND TENSILE STRENGTH OF DISPERSIVE CLAY |
| WANG Zhongni，FAN Henghui，HE Zhiqiang，NIE Yong，LU Lina |
| (College of Water Resources and Architectural Engineering，Northwest A and F University，Yangling，Shaanxi 712100，China) |
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Abstract The influence of modifiers on dispersity and tensile strength of dispersive clay were investigated using pin-hole，crumb and uniaxial tensile tests. The modifier for dispersive clay constitutes of aluminium chloride，trichloroacetic acid and polyacrylamide. The aluminium chloride and the trichloroacetic acid modify the chemically dispersive clay and the polyacrylamide modifies the physically dispersive clay. Results show that the dispersity is reduced and the tensile strength is increased with the increasing of the modifier content. The chemically dispersive clay is turned into non-dispersive when the aluminium chloride content is 0.3% and the tensile strength is increased slowly with the increasing of the aluminium chloride content. When the trichloroacetic acid content is 0.9%，the dispersive clay became non-dispersive and the tensile strength reaches the maximum value. The physically dispersive clay was changed into non-dispersive when the polyacrylamide content is 0.2%. The modifier for dispersive clay not only modify the dispersity but also raise the tensile strength 30% to 70%. The modification mechanism is a series of physical and chemical reactions of the modifiers with soil particles. The aluminium chloride increases the cationic content and reduces the alkaline pH and the trichloroacetic acid reduces the alkaline pH to modify the chemical dispersive clay. The polyacrylamide promotes the formation of granular structure and the resistance to erosion is enhanced. Besides，the tensile strength reduces with the increasing of moisture content and the reducing of the degree of compaction.
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Received: 17 January 2014
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2015, Vol. 34 
