Flowable Fill for Rapid Pavement Repair

The federal, state, and local highway authorities in the United States invested $3.9 billion in the rehabilitation of roughly 8,000 mi of pavement in 2008. This significant investment emphasizes the importance of ensuring that rehabilitation techniques perform well to help reduce the high annual cost for repairs. The repair of pavement base layers with compacted lifts of crushed aggregate requires specialized labor and equipment, contributes significantly to total construction time, is very difficult to perform—particularly in restricted access areas—and often results in a poorly constructed repair and loss in performance. Flowable fill technology has shown some success when used for backfilling patches and utility cut repairs. The purpose of this paper is to present performance and cost advantages of using preblended flowable fill for rapid repair of damaged areas in highway and airfield pavements. Eleven commercially available flowable fill blends were evaluated with laboratory and field testing methods. The laboratory evaluation consisted of standard material characterization testing including compressive strength, flowability, hardening time, and excavatability. Field testing included constructing and trafficking simulated utility cuts and full-depth patches in existing pavements. An examination of structural capacity, surface deformation, and visible surface distress was conducted for each repair at regular traffic intervals. In addition, construction time, difficulty, and cost were compared with those of a traditional aggregate repair. Testing results indicate that backfilling utilities and patches in pavements with flowable fill reduce the potential for premature failure, reduce construction time, and reduce total project cost while increasing repair performance.