Effect of Fibers on Properties of Clay

The use of natural fibers such as coir for soil improvement is highly attractive in countries like India where such materials are locally and economically obtainable, in view of the preservation of natural environment and cost effectiveness. This paper compares the effect of random inclusion of locally available coir fibers and commercial polypropylene fibers on compaction characteristics and California Bearing Ratio (CBR) values of soil. Standard Proctor tests and CBR tests are done on locally available cohesive soil (CH) with low percentage of reinforcement (0ndash1.5% by weight of oven-dried soil). The Maximum Dry Density (MDD) of fiber stabilized soil goes on decreasing and Optimum Moisture Content (OMC) goes on increasing with increase in percentage addition of coir and polypropylene fiber, irrespective of the percentage of addition of fiber. CBR test results reveal that the inclusion of randomly distributed fibers in soil increases the CBR values of the soil by two times. Coir fibers show very close percentile improvement in CBR value of soil when compared with polypropylene stabilized soil. Hence the inclusion of discrete coir fibers in random fashion significantly improves the CBR value of clay and hence could be effectively used for pavement sub-grade purposes