Camouflet Repair Alternatives

Abstract

The inability to operate aircraft on a runway after an attack on an airbase poses significant operational challenges. To address limitations of legacy airfield damage repair (ADR) equipment, materials, and tactics, the U.S. Air Force Air Combat Command began the ADR Modernization program, which eventually transitioned to the Rapid ADR (RADR) program. Within the RADR program, this project's objective was to investigate repair materials and methods for camouflets (i.e., subsurface cavities created by the penetration and detonation of an explosive ordnance).The objective was accomplished through laboratory testing and full-scale testing at the Silver Flag Exercise Site at Tyndall Air Force Base, FL. A method was developed to quickly provide reasonable camouflet volume estimates. Various repair materials were used to repair simulated camouflets that were trafficked at 30-min to 2-hr cure times with a load cart simulating C-17 aircraft. Repairs sustained 112 passes up to 1,568 passes. Repair performance was controlled primarily by existing concrete slab thickness and strength; repair material strength had no perceivable impact (all other factors being equal, this would not be expected to be the case). Repair performance was not adversely affected for the suggested 30-min cure time.

Development of an integrated pavement screed for screeding asphalt or concrete crater repairs

“…The CTS flowable fill tested in this project was the second batch of material supplied by CTS (denoted FF-CTS-2) during the process of formulating a product following military specification MIL-DTL-32527 that details requirements for rapid-setting flowable fill backfill materials (Table 2.1). The first batch of CTS flowable fill was evaluated in Cox and Carr (2018) and exhibited excessive strengths (ranging from 2,000 to 2,750 psi at 28 days). After reformulating their material, CTS provided FF-CTS-2 in 3,000-lb supersacks (approximately 1 yd 3 ) for further evaluation.…”

“…Cylinders were cast for ASTM C39 (2018) compressive strength testing (three replicates), and ASTM D6103 (2017b) flow consistency tests were conducted (two replicates). These two tests represented a simplified screening method relative to the testing in Cox and Carr (2018) and were chosen primarily to assess flowability and strength in a balanced manner. Figure 2.1 provides results from these tests for various SVM7 gate settings (i.e., various w/c ratios).…”

Evaluation of a prototype integrated pavement screed for screeding asphalt or concrete crater repairs

“…FF materials placed with the wet method via the volumetric mixer described in Section 4.3.3 were evaluated for ASTM D6103 (2017b) flow consistency (two replicates) and ASTM C39 (2018) compressive strength (three replicates). These two tests represented a simplified screening method relative to the testing in Cox and Carr (2018) and were chosen primarily to assess flowability and strength in a balanced manner. Each FF material sample was obtained from the mixer's chute, and samples were obtained at various water-cement (w/c) ratios that are controlled by the mixer's flow gate setting.…”

“…Third, lateral shoving, severe or not, can leave a wandering joint rather than a straight joint; the cutoff wheel creates a straight joint with a clean vertical face that is much easier to match when paving the adjacent lane. (Cox and Carr 2018;Cox and Hoffman 2019) have also evaluated other commercially available FF materials for the interest of expanding the list of technically acceptable products. This project presented the opportunity to evaluate additional untested materials since backfill characteristics were not pertinent to the project as long as they were reasonably representative of typical FF materials.…”

“…This project presented the opportunity to evaluate additional untested materials since backfill characteristics were not pertinent to the project as long as they were reasonably representative of typical FF materials. Cox and Carr (2018) and Cox and Hoffman (2019) evaluated two different CTS Flowable Fill (Mil. Spec.)…”