Evaluation of Strength Properties of Subgrade Materials Stabilized with Bio-Enzyme

Abstract

In the recent studies many chemical have been emerged and used as stabilizing agent. One of such chemical (Bio-enzyme) was used in this study as a stabilizing agent. Bio-enzyme is prepared locally from fermented vegetable and fruits waste. These products are natural, nontoxic, non-corrosive, nonflammable liquid and environmentally harmless. In this research, Bio-enzyme was prepared and used in varying proportion to stabilize laterite samples collected from different locations. Detailed laboratory experiments (Classification tests and CBR) were conducted to evaluate the effects of Bio-enzyme at varying dosage after 24 hours of curing of specimens. The percentage passing through sieve No. 200(75 micron) was less than 35%., according to ASHTO and clause 6201 of Federal Ministry of Works and Housing (F.M.W & H) Specification Requirements, sample A is (A-2-5), sample B is (A-2-4) while sample C is classified as A-2-6 and they are silty or clayed gravel and sand. Sample A is a good subgrade, subbase or base materials based on highest CBR values (at 20% bio-enzyme dosage, Sample A (102.50%) and sample B (69.40%) & at 10% sample C (33.2%). Sample B can also be used as subgrade or subbase materials where light traffic is considered and sample C is suitable as filling materials as evident in their CBR value. It has been observed that Bio-enzyme treated soil shows significant improvement in terms of the dry density and CBR value. Presence of Bio-enzyme in the soil samples led to increase in the C.B.R by 10-20% as compared to the control). However, it is recommended that assumption should not be made that Bio-enzyme is considered suitable for all type of soil and long term effect of it should also be examined.