On the Utilization of Fly Ash and Cement Mixtures as a Landfill Liner Material

Abstract

Cement was added to class F type of fly ash in the proportion of 0, 2, 5 and 10 % to study for its suitability as a landfill liner material. Mixtures were compacted to their optimum moisture content (OMC) and maximum dry density (MDD). The results from the consolidation tests showed a relatively lower value of compression index for all the mixtures indicating the settlement due to application of overburden pressure would be small. Hydraulic conductivity of the samples were found to be decreased with the increasing the load. However, none of the mixtures exhibited a hydraulic conductivity value less than 10−9 m/s, a limiting criterion set by various environmental agencies for the material to be used as a landfill liner. However, mixtures of 90 % fly ash + 10 % cement compacted at 5 % wet of OMC-MDD exhibited a hydraulic conductivity value less than 10−9 m/s. On drying, all the mixtures shrunk marginally. The unconsolidated undrained test results indicated that the shear strength parameters increase with increase in the cement content in the mixtures.