Applicability of Clay Soil Stabilized with Red Mud, Bioenzyme, and Red Mud–Bioenzyme as a Subgrade Material in Pavement

Abstract

The present work evaluates and compares the performance of clay soil stabilized with red mud, bioenzyme, and red mud–bioenzyme as a subgrade material in pavement construction. Finite-element simulations have been performed using PLAXIS-2D to evaluate pavement parameters, such as surface deflection, compressive strain at the top of the subgrade layer, and tensile strain at the bottom of the asphaltic layer. Based on strain values, the rutting life and fatigue life of stabilized subgrade pavement have been evaluated. The effect of various axle loads (40 to 280 kN) and climatic conditions (20°C to 40°C) on pavement parameters have been studied. The results show that the compressive strain and tensile strain in pavement increase with an increase in axle loads. The fatigue life of soil–red mud, soil–bioenzyme, and soil–red mud–bioenzyme subgrade pavements are improved by 4 times, 6.5 times, and 13.4 times, respectively, and rutting life is improved by 9.3 times, 20.5 times, and 38.9 times, respectively, as compared with clay soil subgrade pavement. The strain and surface deflection values of stabilized subgrade pavements are found to be 30% to 55.4% and 15% to 42.7% lower, respectively, than clay soil subgrade pavement. Based on analysis, optimum axle load and design life of stabilized subgrade pavements have been discussed. The present study describes the applicability of clay stabilized with red mud, bioenzyme, and red mud–bioenzyme as a subgrade material in pavement. The use of red mud, bioenzyme, and red mud–bioenzyme increase the strength of the weak clay soil subgrade layer. The increased strength will offer additional resistance to the pavement to withstand the load generated by vehicular movement. The use of red mud will also reduce the land-associated problem faced by aluminum industries for aluminum effluent safe disposal. The service life of stabilized subgrade pavement is 4 times to 13 times higher than the service life of clay subgrade pavement. The surface deflection values of stabilized subgrade pavements are found to be 15% to 42.7% lower than clay soil subgrade pavement. This improves the riding comfort for the passengers. The study reveals that the movement of overweight vehicle reduces the service life of pavement. The rate of deterioration of pavement life is faster under higher temperature. The study also suggests the probable axle load that can be allowed on the stabilized subgrade pavement.