Investigation of random inclusion of bamboo fiber on ordinary soil and its effect CBR value

Abstract Stability of any structure depends on strength properties of underground soil on which it is constructed. Structures basically transfer all the loads comes on itself directly to the ground. If the underlying soil is not stable enough to support transferred loads then various types of failure occur such as settlement of the structure, cracks and so on. To solve this issue, soil improvement is necessary because it not only lowers the construction cost but also cuts the risk of any damage of structure later on. Numerous improvement methods can be adopted to make ordinary soil stable enough to support the structural loads. In this research work a number of tests were conducted using both ordinary soil and fiber reinforced soil. Soil samples for unsoaked and soaked CBR tests were prepared at its maximum dry density analogous to its optimum moisture content in the CBR mould with and without fiber. The reinforcing agent used in this study are natural bamboo fibers having diameter of 3 and 6 mm and length of 10 and 20 mm respectively. The proportion of bamboo fiber by waterless weight of normal soil was used as 0.20, 0.40, 0.60, 0.80, 1.00, 1.20 and 1.40%. Bamboo fiber is natural fiber, acts as a strengthening material for ordinary soil. It binds the soil particles together and helps in reduction of rapid change in volumetric properties. Addition of fiber improves the ductility behavior and increases the CBR value of ordinary soil. It was observed from the test results that unsoaked and soaked CBR value of soil increases with the increase in length and diameter of bamboo fiber. It was also found that increasing the percentage of bamboo fiber increases the CBR value of reinforced soil, and this increment is significant at fiber dosage of 1.2%. This significant increase of CBR value will diminish the thickness of pavement