| Summary: | 碩士 === 淡江大學 === 土木工程學系 === 92 === The purpose of this thesis is to study the engineering properties of a clay mixed by fly ash and lime. Fly ash is a solid waste material usually from burning coal by the power plant; lime is a relatively cheap material and used in soil improvement extensively. Both of them can be utilized in soil improvement, but also reduce the environmental problems.
There are thirteen combinations of clay-fly ash-lime mixtures in this study. The fly ash content ranges from zero to twenty percent, and the lime content ranges from zero to ten percent, on the dry weight basis. In this study, the tests conducted include the unconfined compression tests, direct shear tests, and one-dimensional consolidation tests. The results indicate that the improvements on engineering properties are as followings.
(1) With the addition of fly ash and lime, the maximum dry density of each combination decreases and the optimum water content increases.
(2) The strength of clay-fly ash-lime mixtures generally increases with the curing time. The strength of the specimen that cured for seven days reaches at least 68% of the strength of specimen that cured for twenty-eight days.
(3) Compared with the pure clay, the change of the clay mixed with fly ash and lime in the angle of internal friction is not significant, but the cohesion increases.
(4) The unconfined compressive strength of clay increases with the decrease of its water content.
(5) The compression index decreases with the addition of lime and fly ash mixes.
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