<p><p><figure id='attachment_2606' style='max-width:496px' class='caption aligncenter'><img class="wp-image-2606 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph showing EPS Geofoam Blocks Being Placed." width="496" height="308" /><figcaption class='caption-text'> EPS Geofoam Blocks Being Placed (Phtograph from Elias et al.( 2006))</figcaption></figure><h2>Basic Function</h2>Lightweight fill can be used to reduce settlement and increase stability. It can also be used to reduce the static and seismic horizontal forces applied to earth retaining structures.<br><h2>Advantages:</h2><ul> <li>Accelerated construction</li> <li>Reduced structural requirements for resisting lateral loads</li> <li>Reduced settlement and stability problems</li> <li>Suitability for wide variety of projects</li></ul><h2>General Description:</h2>Lightweight fills have a lower unit weight than regular fills and have been used for roadway embankment construction and for other applications in combination with other technologies to reduce the magnitude of the applied loads. Lightweight fills include geofoam; cellular concrete; wood fiber; shredded tires; Expanded Shale, Clay, and Slate (ESCS); fly ash; boiler slag; and air cooled slag.<br><h2>Geologic Applicability:</h2><ul> <li>No geologic or geometric limitations</li> <li>Some types of fills should not be used below the ground water table.</li></ul><h2>Construction Methods:</h2>Many types of lightweight fills have been used for roadway embankment construction. Geofoam can be placed in blocks. Wood fibers and ESCS are placed in layers and can be compacted if necessary. Certain foams and slurries are blended and placed using forms.<br><h2>Additional Information:</h2>Lightweight fills with lower unit weights are generally more expensive. Availability affects selection and economics of the different lightweight fills. Using lightweight fill can require less labor for placement than conventional fills.<br><h2>SHRP2 Applications:</h2><ul> <li>Embankment and roadway construction over unstable soils</li> <li>Roadway and embankment widening</li></ul><h2>Example Successful Applications:</h2><ul> <li>New York State Route 23A – New York</li> <li>Roadway Lane Addition Southeast – Michigan</li> <li>Maine Turnpike Beech Ridge Road Overpass - Maine</li></ul><h2>Complementary Technologies:</h2>Can be used by itself or can be used with MSE walls, cantilever pile walls, geosynthetic reinforced embankments, and reinforced soil slopes.<br><h2>Alternate Technologies:</h2>Competes with many other ground improvement technologies including excavation and replacement, reinforcement technologies, and load transfer methods.<br><h2>Potential Disadvantages:</h2><ul> <li>Increased material cost</li> <li>Environmental concerns</li> <li>Long-term performance</li> <li>Need to encapsulate some types of fills</li> <li>Some types of fill are only locally or regionally available</li> <li>Availability of fill influences cost</li></ul><h2>Key References for this Fact Sheet:</h2>Elias, V., Welsh, J., Warren, J., Lukas, R., Collin, J. G., and Berg, R. R. (2006). Ground Improvement Methods - Volume I, Federal Highway Administration, NHI-06-019.</p><p>Stark, T.D., Arellano, D., Horvath, J.S., and Leshchinsky, D. (2004a). “Guideline and recommended standard for geofoam applications in highway embankments”. NCHRP Report 529 (Project 24-11), National Cooperative Highway Research Program, Transportation Research Board, Washington, D.C.</p><p>Stark, T.D., Arellano, D., Horvath, J.S., and Leshchinsky, D. (2004b). “Geofoam applications in the design and construction of highway embankments”. NCHRP Web Document65 (Project 24-11).</p></p>