Characterization of Lime and Gypsum Amended Class F Fly Ashes As Liner Materials

A liner material apart from having practically lower hydraulic conductivity values should be environmentally safe. This paper apart from addressing the environmental concern associated with the use of fly ashes, also deals with their hydraulic conductivity behavior when the fly ashes are stabilized with lime alone or in combination with gypsum. The hydraulic conductivity studies were carried out in the laboratory by standard falling head test method. The addition of gypsum to lime treated fly ashes in minimizing the leaching of lime has also been investigated, and it is observed that a good correlation exists between lime leachability and hydraulic conductivity. It has been observed that the leaching of trace elements can be minimized by the addition lime along with gypsum. It is quite interesting to note that the gypsum which greatly minimizes the lime leachability also reduces the hydraulic conductivity very efficiently.