| Abstract:A series of unconfined compressive strength tests were carried out on engineering slurries stabilized with Super-absorbent Polymer at different liquid limits. The influence of the liquid limit of slurry on the stabilization efficiency is discussed. Meanwhile, the impact of kaolin clay on the stabilization efficiency at same liquid limit was compared. Finally, based on XRD and SEM microscopic experiments, the micro-mechanism of influence of liquid limit and kaolin on the strength improvement was revealed. The results showed that as the liquid limit of the slurry increased, the unconfined compressive strength (qu) of stabilized soil gradually decreased, that is the solidification efficiency significantly decreased with the increase in slurry liquid limit. When the liquid limit increased by 10%, qu decreased by 48.2% on average. On the other hand, qu of stabilized soil significantly increased by adding kaolin clay. This effect on the strength enhancement greatly enhanced with the curing times. By adding 40% kaolin clay at 90 of curing, qu increased by 1.17 times. The microscopic test results showed that the change of liquid limit had little effect on the magnitude of hydration product. The main reason for qu decreasing with liquid limit is that the micro pores of stabilized soil increased with the increase in liquid limit, resulting in a loose fabric with the increase of slurry liquid limit. Whereas, the amount of hydration products significantly increased for stabilized soil by adding kaolin clay, leading to the enhancement of cementation structure of stabilized soil, eventually resulting in the strength improvement of stabilized soil. These behaviors suggested that for the utilization of engineering slurring in actual projects, the adjustment of liquid limit of slurry onsite can be used to improve the stabilization efficiency, meanwhile, kaolin-based wastes (such as kaolin tailings) can be adding as additional binder to improve the stabilization efficiency, which meeting the green and environmental protection concept. |
