The performance of soft clay soil stabilized with recycled gypsum in wet environment

Takeshi Kamei, Aly Ahmed, Keizo Ugai

In the proceedings of: GEO2011: 64th Canadian Geotechnical Conference, 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 5th Pan-American Conference on Teaching and Learning of Geotechnical Engineering

Session: Laboratory Testing

ABSTRACT: The use of recycled gypsum, which is derived from gypsum waste plasterboard, has recently started in Japan and it is a vital to know the durability of soil stabilized with such waste in a wet environment because gypsum is soluble material. The present study investigates the influence of wet environment on the compressive strength, dry unit weight and durability performance of soft clay soil stabilized with recycled gypsum and Furnace cement under the effect of wetting and drying cycles, referred to as wet environment in this study. Standard cylindrical stabilized soil specimens were prepared and cured for 28 days in a controlled room with constant temperature and humidity. After the curing process, the tested specimens were subjected to different numbers of wetting-drying cycles, and then tested for unconfined compressive strength, moisture content and volume change. Results indicated that the unconfined compressive strength increased with the increase of recycled gypsum content for different wetting-drying cycles investigated. The increase of recycled gypsum content is associated with the increase of dry unit weight, as well as decreases of moisture content of stabilized specimens for different cycles of wetting and drying investigated. The unconfined compressive strength of soils stabilized with recycled gypsum and Furnace cement gradually decreases with an increase in the number of wetting and drying cycles, while the early cycles have the greatest effect on the durability compared to the effect of later cycles. Generally, the influence of wetting-drying cycles on the unconfined compressive strength, durability and volume changes of clay soil stabilized with recycled gypsum and Furnace cement is not significant and this is evidence that the use of recycled gypsum to stabilize the soft clay soil achieves acceptable durability. This study indicates the effective use of recycled gypsum, which is derived from gypsum waste plasterboard, contributes to develop a sustainable society reduces the huge quantities of gypsum waste, cut off the cost disposing and meet sound environment.

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Cite this article:
Takeshi Kamei; Aly Ahmed; Keizo Ugai (2011) The performance of soft clay soil stabilized with recycled gypsum in wet environment in GEO2011. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GEO11Paper308,author = Takeshi Kamei; Aly Ahmed; Keizo Ugai ,title = The performance of soft clay soil stabilized with recycled gypsum in wet environment ,year = 2011}