Abstract:
Clays being expansive in nature poses a great challenge in civil engineering. When encountered with water they undergo volumetric changes; not only damaging the super structure but also experience a sudden loss in strength leading to ultimate failure.
Terrazyme an enzyme has been used to improve the strength properties and reduce swelling of high plastic clayey and low plastic clayey soil obtained from Ballewala, Nandipur, Pakistan. Hight plastic soil was made by mixing low plastic soil with twenty-five percent of bentonite. Terrazyme increased Maximum Dry Density (MDD), California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS) and reduced the swell potential of both clays. For low plastic clay Terrazyme increased the MDD by 1.4 percent; OMC by 5.9 percent. For high plastic, MDD was increased by 2.5 percent; OMC by 12 percent. UCS after 28 days of curing it increased by 177 percent and 253 percent for CL and CH respectively. UCS after 28 days of soaking increased by 130.2 percent and 171 percent for low plastic clay (CL) and high plastic clay (CH) respectively. Whereas LL was reduced by 3.8 percent and 5.2 percent for CL and CH respectively. The un soaked CBR value was increased by 230.5 percent and 292.6 percent for CL and CH respectively. The soaked CBR value increased by 195.5 percent and 300 percent for CL and CH respectively. Swell potential of CL and CH was reduced by 49.3 percent and 35.3 percent respectively. Cation Exchange Capacity (CEC) was reduced by 3.7 percent and 6.1 percent.
