This report documents the repair process of five craters in cold weather utilizing rapid-setting flowable fill (RSFF) and rapid-setting concrete (RSC). The work discussed herein supports the Rapid Airfield Damage Recovery (RADR) Program, in which the main objective is to develop capabilities to rapidly repair damaged airfield pavements for the full spectrum of operational scenarios. The purpose of this report is to document constructability, to collect early-age properties pertinent to the ability of these crater repair techniques to carry aircraft traffic, and to measure performance by exposing crater repairs to simulated aircraft traffic. Crater repair testing occurred at the Frost Effects Research Facility at the ERDC Cold Regions Research and Engineering Laboratory in Hanover, NH. Results showed RSFF could be a suitable cold-weather backfill. Aluminum sulfate was tested as an additive for use in cold weather, but repairs utilizing it did not perform well. The most efficient manner of using RSFF in cold weather was to heat the mix water. With heated mix water, a rapidly placed pavement repair was able to withstand 100 passes of an aircraft load cart after approximately 2 hr of cure time where RSFF was the backfill and RSC was the cap.
The U.S. Air Force Civil Engineer Center (AFCEC) began the Rapid Airfield Damage Recovery (RADR) Modernization Program to develop technologies to address operational limitations of current RADR equipment, materials, and tactics. One of the most critical activities in the crater repair process is the finishing of rapid-setting concrete material used to cap repairs. Finished repairs must meet roughness quality criteria (RQC) in order to prevent damage to fighter aircraft. The concrete screeds used previously were consistently able to meet this criteria, however they required three dedicated personnel to operate. The quantity of crater repair team members is limited, so AFCEC desires a reduction in manpower requirements for rapid-setting concrete finishing. To address this shortfall, five commercially available screeds were evaluated by conducting a total of 14 crater repairs. Screeds were ranked according to the following attributes: (1) speed, (2) ease of setup and operation, (3) ease of transport, (4) operator exertion level, (5) cost, and (6) quality of finish. The number of personnel required to operate each screed was also recorded. The AutoSkreed ® was recommended for consideration as a suitable screed, but several modifications are recommended. The vibratory manual screed and magnesium bar screed were recommended as preferred alternatives. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.
Large volumes of very high moisture content fine-grained soils (very high-moisture soils (VHMS)) are encountered annually. Stabilisation of these soils has been documented as a promising approach for disposal or reuse. Construction using stabilised fine-grained soils with high moisture contents is highly dependent on strength gain with time. This study evaluated the ability of handheld gauges to provide a rapid strength index in VHMS. The results obtained from pocket penetrometer, pocket geotester and pocket vane shear set were evaluated. Testing matrices included using three fine-grained soils and five types of Portland cement. Handheld gauges were used to measure a strength index for numerous cases, resulting in more than 2000 readings with each of the gauges. Approximately 300 unconfined compression tests were also conducted and the results were used to develop strength correlations to handheld gauge indices. The results showed that, in general, there was no considerable proximity difference between the pocket geotester and the pocket penetrometer, but there was a considerable difference relative to the pocket vane shear set. A comparison between the coefficients of variation showed the pocket geotester to be the most repeatable. It is noted that these devices only provide index values and additional tests are always recommended on field samples.
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 tri-service 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. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.
Very high moisture content fine-grained soils are plentiful in wetlands, river basins, and after floods. They can be problematic and require disposal facilities to be constructed in some instances. Any means of handling or re-using these materials is potentially appealing. Using chemical stabilization (e.g., Portland cement) can enhance strength, but the resulting product can be brittle. Adding polymer fibers as a secondary stabilizer can add noticeable ductility while offering at least some strength and stiffness benefits. Two fiber types and Portland cement were mixed into three soils with varying properties at elevated moisture content and tested for shear strength via: (1) unconfined compression (UC), and (2) with hand-held gages. Fiber-reinforced and non-fiber-reinforced specimens were compared in terms of shear strength, elastic modulus, and ductility. Fiber addition, in general, increased shear strength, and the level of increase was affected by soil organic content. Ductility was considerably improved by fiber addition. Correlations were developed by soil type so that conservative elastic modulus values could be calculated from shear strength, and it was observed that fibers increased elastic moduli values.
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