<p><p><figure id='attachment_2580' style='max-width:1078px' class='caption aligncenter'><img class="wp-image-2580" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of a geocell filled with sand." width="1078" height="808" /><figcaption class='caption-text'> Geocell infilled with soil (Source: Jie Han)</figcaption></figure></p><p><figure id='attachment_2579' style='max-width:1076px' class='caption aligncenter'><img class="wp-image-2579 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of sand being dumped into geocells during construction of a roadway." width="1076" height="807" /><figcaption class='caption-text'> Geocell-reinforced road construction (Courtesy of Jie Han, University of Kansas)</figcaption></figure><h2>Basic Function:</h2>Geocells are a three-dimensional geosynthetic product that can be used for subgrade, subbase, and base confinement to ultimately increase pavement service life and reduce pavement thickness.<br><h2>Advantages:</h2><ul> <li>Provide lateral confinement to infill material and thus increase the stiffness and strength of reinforced soils.</li> <li>Reduce creep of recycled asphalt pavement and rutting deformations of granular bases.</li> <li>Increase the life of unpaved and paved roads and reduce the required base thickness.</li> <li>More cost-effective when sand or rounded gravel is used.</li></ul><h2>General Description:</h2>Geocells are a three-dimensional interconnected honeycomb type of geosynthetic used to confine granular bases to increase their stiffness and strength for roadway applications. Geocell enhances the system performance and life expectancy.<br><h2>Geologic Applicability:</h2><ul> <li>Geocells can be used with almost any base/subbase materials. Geocell has been used on soft to firm subgrade.</li> <li>Geocells typically is more cost-effective when sand or rounded gravel is used.</li></ul><h2>Construction Methods:</h2>During construction, geocells have to be first stretched to the desired width and fixed to a leveled surface. A layer of geotextile is often placed under the geocells to separate the infill material from the underlying soil. The infill material is then poured into the pockets of the geocells and the infill material is compacted to the desired density.<br><h2>Additional Information:</h2>Like other geosynthetic products, geocells are usually made from polymeric materials by welding, sewing, or bodkin bars. Currently HDPE and Novel Polymeric Alloy (NPA) types of geocells are commonly used. For convenient transportation, most geocell products have a foldable three-dimensional geometry (often honeycomb shaped after stretched). Today, HDPE and NPA types of geocells have been successfully used to reinforce bases/subbases and subgrade layers in unpaved roads and some paved roads. The key obstacles preventing more widespread use of this technology are: (1) lack of a design method; (2) lack of QC/QA methods, (3) cost of geocells, (4) difficulty in compaction, and (5) limited documented case histories.<br><h2>SHRP2 Applications:</h2><ul> <li>New Embankment and Roadway Construction over Unstable Soils</li> <li>Roadway and embankment widening</li> <li>Stabilization of Pavement Working Platforms</li></ul><h2>Example Successful Applications:</h2><ul> <li>Flexible pavement with geocell-reinforced aggregate subbase, Delaware county, PA</li> <li>Geocell-reinforced unpaved roads during Spring thaw, Vermont, USA</li> <li>Performance of geocell-reinforced RAP bases over weak subgrade under full-scale moving wheel loads, the University of Kansas, USA</li></ul><h2>Complementary Technologies:</h2>Geocell confinement is often used with nonwoven geotextile as a separator between subgrade and infill material.<br><h2>Alternate Technologies:</h2>Geogrid reinforcement, thicker unreinforced base/subbase, lime or cement-stabilized subgrade, and excavation and replacement of subgrade.<br><h2>Potential Disadvantages:</h2><ul> <li>Limited test data for long-term performance</li> <li>Limited demonstration of life-cycle cost benefits.</li> <li>Limited QC/QA and design methods</li> <li>Limited documented case histories</li> <li>Difficulty in compaction of infill materials</li></ul><h2>Key References for this technology:</h2>Al-Qadi, I. L., and Hughes, J. J. (2000). "Field evaluation of geocell use in flexible pavements." <em>Transportation Research Record: Journal of Transportation Research Board</em>, 1709, 26-35.</p><p>Han, J., Pokharel, S.K., Yang, X., Manandhar, C., Leshchinsky, D., Halahmi, I., and Parsons, R.L. (2011). “Performance of geocell-reinforced RAP bases over weak subgrade under full-scale moving wheel loads.” <em>ASCE Journal of Materials in Civil Engineering.</em></p><p>Henry, K. S., Olson, J. P., Farrington, S. P., and Lens, J. (2005). <em>Improved Performance of Unpaved Roads During Spring Thaw</em>. <em>USACE ERDC/CRREL TR-05-1</em>, Engineer Research and Development Center, Cold Region Research and Engineering Laboratory, Hanover, NH.</p><p>&nbsp;</p></p>