Evaluation of Strength Characteristics of Compacted Deltaic Chikoko Clay Stabilized with Rice Hush Ash

Abstract

One of the key parameters usually considered in soil improvement techniques is strength gain. Chikoko clay is a muddy weak clay soil commonly found along the coastal shelf Rivers, Bayelsa, Delta and other coastal states of Nigeria. Deltaic chikoko clay is a weak soil with low bearing capacity that requires some forms of stabilization and strength enhancement. Chikoko clay obtained from Eagle Island in Port Harcourt, Nigeria was stabilized with 2, 4, 6 and 8% of Rice Husk Ash. The engineering characteristics of Reduced British Light (RBL) compacted Deltaic Chikoko clay were assessed. Unconfined Compressive Strength (UCS) was taken after 7, 14 and 28 days curing. The UCS values decreased with increase in water content relative to optimum for the compactive efforts. Addition of Rice husk Ash from 4 – 6% increased the UCS of the compacted stabilized chikoko soil by 14.7%. However, further increase to 8% reduced the UCS by 8.5%. The UCS also decreased by 4.6% after 21 days curing. A maximum unconfined compressive strength (UCS) value of 152 kPa at 6% RHA corresponding to17.8% increment was recorded. Optimal stabilization of Deltaic marine chikoko clay was achieved at 6% RHA. Stabilization of chikoko clay improved its unsoaked CBR value from 8.6% to 17.4%, thereby making the stabilized soil suitable for sub-grade application.