Rajagopal, K., Veeraragavan, A., Chandramouli, S. (2012). “Studies on Geocell Reinforced Road Pavement Structures,” Geosynthetics Asia 2012, Thailand.
Study demonstrates geocell reinforcement increases the stiffness and elastic modulus of pavements by a factor of up to 2.92, in addition to increasing pavement surface life from 16 years to 20 years, and reduces the thickness of granular layers by as much as 50%.
Too often, the scarcity or distance of natural resources, makes the strengthening of highway pavements a costly or lengthy exercise. Building on previous studies by Bathurst, Han, Pokharel and others, this study provides academic proof that Neoloy Geocell reinforcement increases the stiffness and elastic modulus of pavements.
Validation – Field study
A field test was carried out on samples from an access road in Phaltan, Maharashtra, consisting of water bound Macadam and granular sub base. The performance of an Neoloy Geocell reinforced pavement and adjacent unreinforced sections were monitored from March to December 2010, during which there was unusually heavy rainfall. The following observations were made:
- The unreinforced pavement underwent severe rutting and had to be reconstructed at least 3 times
- The unreinforced pavement experienced severe surface depressions
- The Neoloy Geocell reinforced pavement maintained a uniform surface
- There was no change of dimensions when pieces of Neoloy Geocell were exposed to 100°C temperature in an oven for a 1 hour duration
Project installation of the Neoloy Geocell Reinforced Base Layer and infill with GSB (granular sub-base) material
Validation – Laboratory test
The laboratory test was designed to further explore the results of the field study. Water bound Macadam and granular sub base were tested as a subgrade in a test tank. Plate load tests were conducted on 3 different thicknesses of Neoloy Geocell layers. Several tests were performed on varying combinations of Neoloy Geocell and infill material.
Results – Improved modulus performance
Calculations, using Young’s modulus values, showed the following results:
- In field tests, Neoloy Geocell improved elastic modulus by a factor of 2.75
- In laboratory tests, Neoloy Geocell improved elastic modulus by a factor of 2.84 in 50 mm and 100 mm thick sections, and by a factor of 2.92 in a 150 mm thick section
The study also demonstrated the following results:
- Adding a Neoloy Geocell layer significantly reduced the vertical pressures transmitted by the subgrade layers, increasing pavement surface life from 16 years to 20 years
- The use of Neoloy Geocell layer reduces the thickness of granular layers by as much as 50%
Benefits – Low damage, low thickness means reduced cost, faster construction
Using one or more Neoloy Geocell layers was found to increase the structural stiffness of the pavement and its elastic modulus, generating significant benefits:
- Reduced pavement thickness, allowing for a significant reduction in total cost of the pavement system per unit area
- Reduced pavement thickness requiring less material and therefore faster construction
- With fewer materials required, reduced transport costs constituting a reduced carbon footprint