ABSTRACT
ABSTRACT: The potential of three different liquid enzymes to stabilize CL and CH type of soils is evaluated. The evaluation involved the determination of the geotechnical properties of clay soils in their natural state as well as when mixed with three different liquid enzymes, separately. The parameters tested included the particle size distribution, Atterberg limits, compaction characteristics (optimum moisture content and maximum dry unit weight) under standard Proctor compaction energy effort, swell percentage and California bearing ratio (CBR). All tests of the treated samples were repeated after 1-day, 7-day and 28-day curing periods. Results showed that the geotechnical parameters of clay soils are improved very little by the addition of liquid enzymes; plasticity and optimum moisture content were reduced around 5% to 10%, maximum dry unit weight is reduced as negligible as 1%. But, swell percentages and CBR values are increased by 5% to 350% and 5% to 70% depending on the curing period and type of soil treated, respectively. These results imply that although liquid enzymes provide some beneficial effects in CBR values, it is unlikely to be a substitute for CH type of soil as swell percentage increased dramatically.
