California Bearing Ratio and Permeability Behaviour of Fly Ash Reinforced with Geotextiles

Abstract

Two different laboratory tests, i.e., California bearing ratio (CBR) and permeability have been conducted on fly ash both in unreinforced and reinforced with nonwoven geotextiles. CBR test is conducted on fly ash and the values are 11.23 and 16.27% at 2.5 and 5 mm respectively. After reinforcement provided in three different layers, i.e., two layers in middle with fly ash layer in between, one layer each in middle and bottom, and one layer each in top, middle and bottom, the CBR values increases within the ranges between 11.72–17.58% at 2.5 mm and 17.5–22.46% at 5 mm penetration. However, the most improved (i.e., increased) values are observed when reinforcement is provided in three layers at equal interval. The permeability (k) value of well compacted fly ash is 3.30 × 10⁻⁷ m/s. The permeability value decreases after reinforcement has been provided in different layers and within the ranges 8.14 × 10⁻⁸ to 9.8 × 10⁻⁸ m/s and the most improved (i.e., decreased) values are observed in three layers reinforcement at equal interval. The modified permeability value minimizes the seepage of water through a fly ash embankment. So the fly ash and reinforced fly ash can be used as a structural fill and embankment materials.