Effect of ground granulated blast furnace slag–stabilized bentonite soils on flexible pavement design and cost analysis

In this study, the effects of ground granulated blast furnace slag (GGBFS) stabilization of subgrade soil on flexible pavement layer thicknesses and initial construction costs were investigated. For this purpose, Proctor compaction tests were conducted on bentonite (BT) soil samples prepared by adding GGBFS at rates of 5%, 10%, 15%, and 20% by weight. Following these tests, unconfined compressive strength specimens were prepared and tested after curing periods of 3 and 7 days. The results indicated that the highest compressive strength was obtained in mixtures containing 15% GGBFS. In addition, untreated soil and soil samples stabilized with 15% GGBFS were subjected to the California Bearing Ratio (CBR) test after 3 and 7 days of curing. It was determined that the CBR values of the samples containing 15% GGBFS increased by 2.09 and 2.85 times, respectively. Using the CBR values obtained, pavement layer thicknesses were calculated based on the AASHTO 1993 flexible pavement design guidelines, and cost analyses were performed. The results showed that stabilization with 15% GGBFS reduced the initial construction costs by 23.03%.