Performance evaluation of geocell-reinforced pavements

Abstract

Weak subgrades are the common problem in road construction and these weak subgrades lead to large deformation resulting in rutting failure of the pavement structure. These days, Geocells have been widely used to reinforce/stabilise the structures with unbound materials. This paper presents the results of repeated load tests on the unreinforced and geocell-reinforced model pavement sections. The model pavement sections were built in a steel tank of size 2 m × 2 m × 2 m. Stage construction was adopted in the construction of model pavement sections. The geocell layer of varying aspect ratio was considered and in all the geocell-reinforced pavement sections, geocell layer was placed at the interface of subgrade and granular sub-base course layers. Haversine loading was adopted to simulate the vehicular loading. A maximum pressure of 760 kPa (pressure exerted by a truck with single axle and single wheel) was applied at the top of the test section using a hydraulic jack of capacity 100kN. The tests were terminated at 500 loading cycles. The pressure – settlement behaviour of unreinforced and geocell-reinforced pavement sections is reported. The plastic settlement is found to be the predominant mode of settlement which ultimately leads to rutting failure of the pavement. The provision of geocells reduces rutting to an extent of 13–71% and increases the rut life of the pavement sections by a factor of 1.6 to 3.5 with varying aspect ratio and pavement thickness when compared with the respective unreinforced pavement sections. The reduction in plastic settlement (RPS) increases with increase in aspect ratio of geocells and higher aspect ratio (i.e. 0.67) shows maximum reduction in rutting. Geocell reinforcement is also found to reduce surface heaving and the reduction in plastic settlement is quantified in terms of a non-dimensional improvement factor varying in the order of 2.19–2.64 with varying pavement thickness and aspect ratio. The improvement increases with increase in aspect ratio of geocells and higher aspect ratio geocell (i.e. 0.67) corresponds to maximum reduction in rutting, RPS, reduced heaving and maximum improvement factor. The introduction of geocell at the interface of subgrade and sub-base results in more durable, environment-friendly and long-lasting pavement.