Near Northern Kentucky University in Campbell County, Kentucky, access ramps connecting I 275 and 3-Mile Road (shown in Figure 1) were constructed. During construction of those ramps, additional embankments were to be placed on an existing 6-foot by 5-foot box culvert. Both ramps, hereafter referred to as NKU-1 (the exit ramp from I 275) and NKU-2 (the entrance ramp to I 275), cross the culvert. The new embankments would result in fill heights, over the culvert of 30 feet at Station 39+14 of NKU-1 (Figure 2) and 47 feet at Station 11+68 of NKU-2 (Figure 3). The original fill height was approximately 11 feet at NKU-1 and 29 feet at NKU-2. With the use of conventional fill material, loading on the culvert would exceed that which the structure was designed to support. To avoid replacing the existing culvert, a lightweight fill material was needed.

Elastizell lightweight concrete was chosen for construction of the embankments. This concrete is made by blending a preformed Elastizell foam with a cement-water slurry. The resulting fluid forms a discrete cellular concrete that may be placed at densities as low as 20 pounds per cubic foot with a relatively high compressive strength. Elastizell concrete is identified by class and, generally, a lower class indicates a lower density. Because the material is a thin liquid, it may readily be pumped through hoses from the mixing equipment into formed basins (Figure 4). Some common applications for low-density concrete are: roof fills, thermal insulation, fire protection, and stabilizing fills.

This study was performed to determine the engineering properties of this material during and after placement, observe construction procedures for placing the material, and to evaluate its performance as a lightweight fill material.

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The contents of this report reflect the views of the authors who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the of the University of Kentucky, the Federal Highway Administration or the Kentucky Transportation Cabinet. This report does not constitute a standard, specification, or regulation.