Effect of bamboo fiber on lime-treated granitic residual soil strength

Granitic residual soil (GRS) is a common type of soil which makes up about 75% of Malaysia's total land area. It plays a significant role in construction of engineering project including highway, embankment, slope and foundation. However, the properties of soil could be affected by various deteriorating factors and gradation due to exposure to tropical climate that subsequently degrade its strength characteristics. Currently, there are many of research regarding the use of eco-friendly material for sustainable application in engineering project includes the use of renewable material such as natural fibers. Natural fiber particularly bamboo due to it tensile strength, stability and durability commonly being explored like others natural fibers such as banana fiber, seed flax and kenaf as alternative binder in soil stabilization. In this study, the strength properties of treated soil have been carried out by adding designated proportions of bamboo fiber (BF) of Gigantochloa scortechinii (buluh semantan) species into the mixture with dehydrated lime as binding agent. This study was primarily aimed to determine the unconfined strength (UCS) and shear strength by means of Unconfined Compressive Strength Test (UCT) and direct shear box test. The treated soil specimens were mixed with bamboo fiber and hydrated lime of various designated fiber proportions from 0.5% to 5% and hydrated lime (HL) proportion between 2.5% to 5% respectively. The lengths of bamboo fibers were varied from 10mm to 30 mm for both type of test. The results revealed that treated GRS exhibited 15 folds UCS increase to 590 kPa after treatment with 1% BF of 10 mm length fiber, while 4 times increase of shear strength of the treated sample to 321 kPa was observed under direct shear box test.