Effective Design of Flexible Pavement on Treated Expansive Soil

Expansive soil poses plenteous problems to the structures placed over it, such as, road pavements, buildings and canals, etc., mainly because of high swell index induced by its high-water retention capacity. Flexible pavements with expansive soil as a subgrade material are characterized with meager performance mainly due to cracking and differential settlement. The current study engages with the cost effectiveness of treated expansive soil as subgrade material. Lime and stone dust have been blended with soil at varied percentages to enhance the suitability of this mix as subgrade material. To catch on the extent of influence of stabilizing mixture, Modified Proctor and California Bearing Ratio tests have been performed on treated soil. The thickness of various layers of pavement has then been evaluated in conformity with IRC: 37 [1] and then cost analysis has been made for pavements with both untreated and treated subgrade course. It has been discerned that when expansive soil is stabilized with lime-stone dust mix (5–12% by weight of mix), the drop in the cost of flexible pavement is found to be maximum, i.e., 6.55% of cost reduction can be achieved if the pavement subgrade section is made up of treated soil instead of untreated one.