Nishantha Bandara, Elin Jensen, Tarik H. Binoy
Mark Grazioli, Michigan DOT
Kiln dust, Landfills, Michigan, pavement design, Recycled materials, Soil stabilization, Subgrade materials, Undercutting
The standard practice of Michigan Department Transportation (MDOT) to treat unsuitable subgrade is to remove and replace (undercutting) with acceptable materials. In few MDOT projects, soil stabilization techniques were utilized to facilitate construction instead of undercutting. However, neighboring states such as Indiana, Ohio, Wisconsin and Minnesota frequently use soil stabilization techniques to treat unacceptable subgrade soils. Due to rising costs of good quality acceptable materials for remove/replace options and traditional subgrade stabilization materials, MDOT is in need to identify potential recycled materials to treat unacceptable subgrade soils. Recycled materials not only provide cheaper alternatives for subgrade stabilization, they also alleviate landfill problems. Most of the previous studies related to subgrade stabilization were limited to quantifying immediate benefit through construction facilitation. However, there is a need to identify the long-term benefits and/or risks of subgrade stabilization. With satisfactory long-term benefits, subgrade stabilization can be potentially used for optimizing pavement designs that will result in cost effective pavement sections. If there are any long-term risks associated with subgrade stabilization, that may be addressed by remedial actions or limiting usage of those stabilizing materials. This research study is aimed at identifying short-term and long-term benefits and risks of using recycled materials such as Cement Kiln Dust (CKD), Lime Kiln Dust (LKD), fly-ash, concrete fines and other materials for subgrade stabilization.