Assessment of Utilization of Local Songkhla Clay – Rubber Wood Ash Mixture as Landfill Liner

Abstract

In this study, mixtures of Songkhla local clay and Rubber wood ash were studied as a landfill liner. Benson and Daniel (1990) showed that suitable liner properties consist of a hydraulic conductivity lower than 1x10-7cm/s, an unconfined compressive strength less than 200 kPa and a volumetric shrinkage strain lower 4%. In order to determine a appropriate mixture, the clay-fly ash ratios of the mixtures of 100:0 and 80:20 and incubation time of 0, 7, and 28 days, were used. Experimental results show that for the 100:0 mixture (clay only) although its hydraulic conductivity coefficient is lower than 1x10-7cm/s but it is not suitable for use as a liner because its unconfined compressive strength and volumetric shrinkage strain are less than 200 kPa and more than 4%, respectively. On the other hand, for the 80:20 mixture with incubation time of 28 days, all the test results meet the specified criteria. Hence, it is suitable for use as landfill liner.