Use of in Situ Tests in Compaction Control of a Bottom Ash Embankment

Abstract

Since 1994, the Indiana Department of Transportation has constructed numerous recycled materials projects that use bottom ash, fly ash, foundry sand, crushed glass, and tire shreds in transportation facilities. All these projects were constructed in accordance with procedural specifications based on conventional compaction control tests such as the nuclear gauge. However, the nuclear gauge does not give accurate density and moisture content results because of the presence of numerous elements in recycled materials. In addition, sand cone tests are cumbersome and time-consuming. There is a need to develop criteria for in situ test methods such as the dynamic cone penetration test and lightweight deflectometer (LWD) testing. Once an initial criterion is established, criteria for compaction control of similar recycled materials can be developed. In a study, a test pad using coal ash was constructed with a combination of roller passes. On the basis of the results of dynamic cone penetration and LWD tests conducted in the test pad, in conjunction with a combination of roller passes, the criteria for compaction control of bottom ash was provided for the construction of the remaining 11-m-high embankment. The subsequent construction monitoring and postconstruction evaluation of the bottom ash embankment revealed that the criteria are very effective.