Mitigating swelling in unpaved roads with geotextile and geocell composites: an experimental study

The cyclic swell–shrink of expansive soils results in pavement deterioration, manifesting in the form of cracks, uneven settlements and premature failure of pavements. In the present study, two types of geotextiles with tensile strengths of 55 kN/m to 200 kN/m and three types of geocells with cell depths of 100 mm, 150 mm and 200 mm were chosen as reinforcements. Two case studies of unpaved road models were constructed in a large-scale testing chamber with a plate size (B) equal to 200 mm. They comprise case 1 with base and subbase layers consisting of wet mix macadam (WMM) with a total thickness of 400 mm, and case 2 with base and subbase layers laid using WMM with a total thickness of 450 mm. The different reinforcement configurations considered in the two test cases were subjected to moderate to high swell pressures ranging from 400 to 800 kPa. Results showed a significant reduction of surface heave and a substantial improvement in efficiency considering geotextile alone and geocell integrated with geotextile termed as composite reinforcement in an unpaved road layer. In particular, the geotextile with high tensile strength combined with geocell of 200 mm cell depth was found to show greater reduction of surface heave compared to all other reinforcement configurations considered in the study.