Accelerated Pavement Testing of Unpaved Roads with Geocell-Reinforced Sand Bases

Accelerated pavement testing (APT) is an effective method in evaluating pavement performances by applying controlled wheel loading under environmental conditions. This note presents the findings from an accelerated pavement test on unpaved road sections involving geocell reinforcement of sand bases. A total of four unpaved road sections were constructed. Sections 1 and 4 were unreinforced sections first with sand bases and then replaced with aggregate bases after failure. Sections 2 and 3 were sand sections reinforced with novel polymeric alloy (NPA) geocell under an aggregate cover layer. Rut depths developed in each section were measured after a certain number of wheel passes. Horizontal strains at different locations in the NPA geocell were monitored by strain gages. Test results demonstrated that the NPA geocell had a significant effect in improving the stability of unpaved roads and reducing the permanent deformation. Under the particular test condition, the NPA geocell-reinforced sand layer behaved equivalently to the A-1-a aggregate of the same thickness. The deformations of the geocell-reinforced road sections were analyzed. The test also revealed the importance of keeping the geocell structure intact to ensure the adequate performance of NPA geocell-reinforced bases. Strain gage measurements showed that the NPA geocell beneath the wheel path experienced tensile stresses whereas the geocell outside the wheel path experienced compressive stresses.