DOI: 10.5176/2301-394X_ACE13.129
Authors: Anil K.Mishra
Abstract:
Mixture of soil-bentonite are comprised of two truly contrasting soil in regards to the grain size, hydraulic conductivity, chemical activity and strength, when combined in the optimum proportion, can form an excellent seepage liner material that is dimensionally stable and have a low hydraulic conductivity. The performance of the clay barrier to leachate depends on the amount of bentonite present in it. To asses the effect of the variation of the bentonite amount in the mixture study was carried out for two mixtures of soil and bentonite in the proportion of 100:20 and 100:10 by their dry weights. The results showed that an increase in the bentonite fraction in the mixture had a significant effect on the hydraulic conductivity (k) and compressibility of the mixture. With the increase in the bentonite fraction, the k decreased. This decreased was quite significant for lower salt concentration range (i.e. 0 to 0.01 N) of NaCl and CaCl2 solution. With a further increase in the concentration the difference in the k between the two mixtures decreased. Similarly, with an increase in the bentonite fraction in the mixture, the compressibility was also increased. The effect of salt concentration on the compressibility was of less extent for the 100:10 mixture than for the 100:20 mixture. The increase in bentonite fraction in the mixture also increased the compression index (Cc). Similar to k, the effect of bentonite amount on Cc was quite significant at less concentration range (i.e. 0 to 0.01 N).
Keywords: Clay liner; bentonite; salt; swelling; hydraulic conductivity; compressibility
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