Sustainability of lime stabilized road subgrade in mountainous regions of Turkiye

In this paper the use of lime stabilized subgrade for low volume roads in two regions with high mountains and different frost penetration conditions in Turkiye was investigated in terms of design, performance, and cost. Pavements on unstabilized and stabilized subgrade were designed for two regions (Izmir and Van), covering all climate variations. The resilient modulus of the lime stabilized subgrade with different soil pulverization levels for non-freezing and freezing conditions were taken from a previous laboratory study. Frost effects were considered in pavement design using two different approaches, including limited subgrade frost penetration method and reduced subgrade strength method. Detailed application and evaluation were performed for all steps. Lime stabilized subgrades significantly reduced the thickness of base courses, and the benefit of lime stabilization was highly dependent on soil pulverization level. A detailed cost analysis on the unstabilized and stabilized cases found that the use of lime stabilization in the subgrade provided significant initial cost savings. Comparative analysis by using the AASHTO (1993) method and KENPAVE software, and quantity effect of soil pulverization level on the performance of low volume roads from a service life perspective, show that subgrade resilient modulus can be estimated. It is also possible to make correct performance estimation in the field. The results of the study show that lime stabilization is a good solution for low volume roads in the mountainous regions of Turkiye.