Stabilization of bentonite clays in pavement subgrade on Ulubey t1 tunnel alignment with several additives

Variations in moisture content of clays with high plasticity and high swelling potential, result in deformations and bearing capacity problems in light and flexible engineering structures such as highways. By improvement of engineering properties of soil, damages in highway pavement can be prevented.Subgrade of pavement on (Ordu-Ulubey) Intersection - Topçam Highway Km: 6+015-6+405 consist of saturated bentonite clay (CH) belonging to Ca-Na smectite group with normal clay activity. In this study experimental works have been carried out for stabilization of bentonite clay with high swelling potential using high calcium lime and Consolid444+Solidry (C+S) at three different ratios.Evaluation of swelling tests results showed that (C+S) and high-calcium lime change the swelling behavior considerably. Lime additive influences shrinkage behavior more effectively. Both additives improve CBR strength value of soil with higher increase in case with (C+S) additive. 7% lime additive is required to stabilize pavement subgrade according to technical specification of highways whereas 2% of (C+S) provide stabilization except LL, PI and ?dmax criteria. It is observed that, increase of percentages in both additives result in increase of unconfined compression strength of soil depending on curing time. According to the triaxial (UU) test results, there is a similar decrease in cohesion clay and a similar increase in internal friction angle for both additives. Both of the additives eliminated the requirement for subbase and superior materials in pavement design. However, the additive of (C+S) required that plantmix base layer was increased by 5 cm. In this study, according to the cost analysis, it was seen that using lime additive for stabilization was a cheaper method.