10 Jun 2020

PUBLICATION NOTICE: Full-Scale Testing of Commercially Available Cementitious Backfill and Surface Capping Materials for Crater Repairs

Abstract: The Air Force Civil Engineer Center (AFCEC) Rapid Airfield Damage Recovery (RADR) program currently utilizes rapid-setting flowable fill (RSFF) and rapid-setting concrete (RSC) for backfilling and capping crater repairs. These materials have been proven successful through many full-scale tests, troop demonstrations, and live flight trafficking. However, only one proprietary product is currently approved for each material. Two candidate capping materials and one backfill material were evaluated by conducting simulated crater repairs and collecting appropriate data. For capping products, both small (8.5 ft x 8.5 ft) and large (15 ft x 15 ft) repairs were conducted and trafficked with simulated F-15E aircraft traffic. For the backfill material, three small repairs were backfilled and the California Bearing Ratio (CBR) was estimated at cure times of 0.5, 2, and 24 hr. Overall, repairs capped with Western Materials Fastrac 246 failed after only 2,000 passes, so the material is not currently recommended for approval. Repairs capped with Buzzi Unicem Ulti-Pave3® were able to sustain 3,500 passes before trafficking was ceased, so this material is recommended for approval as a crater repair capping material. CTS rapid-setting flowable fill backfill exhibited lower than expected CBR values and did not allow timely percolation of mix water, so it is not currently recommended for approval at this time.

29 Apr 2020

PUBLICATION NOTICE: Laboratory Characterization of Rapid-Setting Flowable Fill

Abstract: Utility Fill One-Step 750® is a rapid-setting flowable fill product that has previously been validated in numerous full-scale demonstrations as an expedient backfill solution for Rapid Airfield Damage Recovery. Although the field performance of Utility Fill One-Step 750® has been extensively documented, a full laboratory characterization has not been conducted. This report analyzes and documents results from several laboratory tests conducted at two water to-product ratios. The tests conducted are based on the suite of tests that make up the triservice spall repair certification program used for rapid-setting concrete products. Tests include strength and set time-related properties, typical parameter control tests for concrete, and tests to determine the mineralogy and chemical makeup of the material. Long-term expansion and contraction properties were also tested. The data presented herein are intended to provide an overall assessment of Utility Fill One-Step 750® and to provide reasonable estimates of various design parameters. The results can be used as a basis for the future development of a formal laboratory certification protocol to down-select other rapid-setting flowable fill products for further evaluation.