Preliminary study on use of terrazyme as a bio stabilizer along with cement and lime in compressed stabilized earth blocks
Stabilizers play an important role in improving the engineering properties of the Compressed Stabilized Earth Blocks (CSEBs).Traditional stabilizers like cement and lime have been popularly used to improve the soil with which CSEBs are prepared. It has been reported that use of lime in combination with cement has improved the long-term strength of CSEBs. Due to the high energy consumption in manufacturing of conventional stabilizers, alternative sources of stabilizers are looked upon. Terrazyme is one such stabilizer, which has been used in various road projects and has found to be a viable low cost non-traditional stabilizer. The use of Terrazyme as a stabilizer, may have a beneficial role in increasing the strength of CSEBs. As no previous attempts have been made to use Terrazyme in the preparation of CSEBs, it was found that understanding its behavior with soil as a necessary. Time related physical properties of a natural soil treated with Terrazyme has revealed that liquid limit reduces with time, while plastic limit increased with ageing. The reduced plasticity index indicates that the soil is becoming less compressible and volumetrically stable. Unconfined compressive strength of soil treated with different dosages of Terrazyme at ageing periods were evaluated, and optimum dosage for the soil was arrived. Addition of Terrazyme has increased the unconfined compressive strength of the soil. Unconfined compressive strengths of soil with/without optimum dosage of Terrazyme along with combinations of cement and lime with time were evaluated. The admixtures-soil combination which yielded the best Unconfined Compressive strength was selected for the preparation of CSEBs. Blocks prepared with Terrazyme had higher wet compressive strength and lower water absorption than other blocks. After two months, the wet compressive strength of blocks prepared with Terrazyme was found 30% to 50% higher than the blocks without Terrazyme, bringing out the beneficial effect of Terrazyme.