<p><p><figure id='attachment_3472' style='max-width:796px' class='caption aligncenter'><img class="wp-image-3472 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Aerial view photograph showing location of project on the interchange of Interstate 39 and U.S. Highway 78 where injected lightweight foam fill was used. Project is in Columbia County, Wisconsin." width="796" height="451" /><figcaption class='caption-text'> Photo from WisDOT Report WI-02-07</figcaption></figure></p><p><div><h2>Project Summary/Scope:</h2>Wisconsin DOT investigated the effectiveness of injected lightweight foam fill in lifting pavement slabs. Four approach slabs, located on Interstate 39 in Columbia County, Wisconsin, were injected with polyurethane foam. The slabs are approximately 6.4 meters (21 feet) long, 3.7 meters (12 feet) wide, and 0.3 meters (12 inches) thick. The injection area for four slabs is about 105 m² (1,100 ft²).</p><p>The target elevation changes varied at both left and right edges of the driving and passing lanes. For these four slabs, it is estimated that 270 kg (600 lb) of polyurethane foam would be used. Two to three holes were drilled through the concrete pavement in the transverse direction, with a total of 40 holes in the four slabs.</p><p>The work started at 7:00 AM, and completed at 6:30 PM on June 21, 2001. The work duration was 11.5 hours including a one-hour delay due to rain. In the morning, the foam injection into two slabs started in the passing lane, followed by two slabs in the driving lane in the afternoon. In the driving lane, two slabs were lifted from 0 to 30 mm (0 to 1.2 inches) at the left edge of the slabs and 0 to 15 mm (0 to 0.6 inches) at the right edge of the slabs. In the passing lane, two slabs were lifted from 0 to 18 mm (0 to 0.7 inches) at left edge of the slabs and 0 to 36 mm (0 to 1.4 inches) at the right edge of the slabs. The project required 1,470 kg (3,240 lbs) of polyurethane, which is five times greater than estimated. The project was successfully completed three times faster than design.</p><p>Because the material flowed through the passing lane to the driving lane, a 6-mm (0.25-inch) elevation increase on the passing lane was observed due to the injection process on the driving lane. Elevation change of the slabs on the passing lane changed from 32 mm (1.25 inches) in the morning to 36 mm (1.42 inches) in the afternoon. Fine cracks were formed in the pavement as a result of the lifting process.<br><h2>Performance Monitoring:</h2>String lines were used to monitor slab rise during injection and were set up on both the left and right sides of the lanes. Four fine cracks were observed in the first slab six months after injection. One additional crack in the first slab of the driving lane was observed five and a half years after injection. The treated pavement generally performed well.<br><h2>Cost Information:</h2>The total cost of the material was $19,440 with a unit cost of $290/m² ($243/yd²). Unit prices of other pavement repair methods are (1) $354.2/m² ($425/yd²) for slab replacement, (2) $38/m² ($45/yd²) for HMA overlay, and (3) $32/m² ($38/yd²) for mud‑jacking.<br><h2>Project Technical Paper:<strong> </strong></h2>Abu al-Eis, K. and LaBarca, I.K. (2007). Evaluation of The URETEK Method^® of Pavement Lifting, Report WI-02-07, Wisconsin Department of Transportation, 30p.<br><h2>Date Case History Prepared:</h2>November 2012</p><p></div></p></p>