The application of geopolymerization method to modify the yellow marl soil of Tabriz

Geopolymers produced by the reaction between solid aluminosilicate and alkaline metal solution have been classified as the third generation binders after lime and portland cement. In current study, the application of the above method to modify the behavior of the yellow marl soil of Tabriz has been evaluated by unconfined compression tests. For this purpose, zeolite and metaclay have been used as sources of silica alumina and sodium hydroxide solution has been used as an alkaline activator. The results of tests have shown the very appropriate effect of the geopolymerization mechanism in treatment the resistance of carbonated clay soil. Meanwhile, the zeolite geopolymer samples have higher resistance than the metaclay ones in all combinations and curing times. The effect of alkaline solution concentration on the strength of zeolite and metaclay geopolymer samples was not the same, so that in the metaclay samples, increasing the molarity of alkali had a negative effect on results. Also, the results show that the rate of change of resistance with time depends on the concentration of alkaline solution so that the treatment effect reduces with inhancement of alkali content. In the optimal sample of zeolite geopolymer (15% zeolite, 12 M alkaline), the uniaxial resistance is about 90.2 kg/cm2, which is about 26 times yellow marl one wherease the optimal metaclay geopolymeric matrix (15% matrix, 4 M alkaline solution) has obtained an unconfined compression strength of about 17.86 kg/cm2. Also in the geopolymer samples, the failure strain has declined by 50% compared to the pure soil.