LEACHING STUDIES ON LIME -STABILISED FLY ASH CUSHIONM. RAMA RAO AND A. SREERAMA RAO
Expansive clays swell and shrink seasonally when subjected to annual moisture changes causing substantial distress to the structures built over them. Many innovative techniques like sand cushion, Cohesive Non-swelling Soil (CNS) layer and Under-reamed piles have been tried to prevent damages to structures founded in these soils. Each one of the techniques, however, bristles with some drawback or the other. The CNS layer technique, which is more often used in canal linings and embankment slopes, has definite drawbacks as subsequent research has shown. In order to overcome these disadvantages, a fly ash cushion stabilized with cement or lime has been tried. This has been found to be not only effective in arresting heave but also in solving, to some extent, the disposal of fly ash which is a hazardous waste material. However, doubts persist in the minds of some as to the durability of lime in lime-stabilized fly ash cushion because lime has a tendency to get carried away in solution by water during the wetting and drying cycles. This work attempts to study the durability of lime in lime-stabilized fly ash cushions. The amount of lime leached depends upon the dry density of fly ash cushion. Higher the dry density, smaller would be the percentage lime leached. Fatigue is noticeable in the process of leaching of lime from fly ash cushion which means that the amount of lime leached reduces with every cycle of wetting and drying. The study has established that the amount of lime leached from the fly ash cushion is quite negligible and that it can be effectively used in stabilizing fly ash cushions for arresting heave of expansive clay beds.
Enter your contact information below to receive full paper.