9 Oct 2024

Unified Facilities Criteria and Unified Facilities Guide Specifications for Sustainable Military Construction : Concrete, Asphalt, Wood, and Life-Cycle Assessment Perspectives

Abstract: Construction materials such as concrete, asphalt, and wood are essential components for Department of Defense (DoD) Military Construction (MILCON) and construction for contingency operations around the world. From housing facilities, to airfields, to magazines and hardened structures, each of these materials fulfill numerous Army building applications. However, greenhouse gas (GHG) emissions stemming from the manufacturing, application, maintenance, and disposal of concrete and steel exact a significant climate burden. Thus, due to their pervasive use and commodity status, the advancement of sustainable concrete, asphalt, and wood materials are a critical driver for GHG mitigation. This report communicates a first step toward decarbonization-focused updates to UFC and UFGS by outlining major specifications related to concrete, asphalt, and wood with near- and long-term strategies to facilitate modernization. The Engineer Research and Development Center (ERDC) is poised to make a significant impact on the identification and integration of sustainable materials to meet regulatory goals for the re-duction of GHG emissions in MILCON. New guidance will be integrated into UFC and UFGS by leveraging unique re-search, development, test, and evaluation (RDT&E) capabilities in materials science, life-cycle assessment, and federal relationships with discipline working groups

7 Oct 2024

Full-Scale Evaluation of Saltwater Concrete for Airfield Pavement Construction and Repair

Abstract: The US Navy has a need to rapidly construct concrete facilities onshore to support contingency operations. Mixing water for concrete is typically specified to be freshwater; however, in many scenarios there are limited amounts of freshwater available for construction. Thus, use of readily available saltwater would be advantageous. This project’s objective was to evaluate the suitability of saltwater as a replacement for freshwater for producing concrete airfield pavement under relevant operational scenarios. Three full-scale test sections were constructed, and performance was evaluated in the context of relatively short design life requirements. First, direct comparison slabs of freshwater and saltwater concrete were constructed and exposed to ambient environmental conditions for one year; periodic concrete strength measurements were made. Next, 8 in. thick and 11 in. thick saltwater concrete pavements were constructed then subjected to P-8 aircraft accelerated loading. Finally, four airfield damage repair techniques were executed using saltwater and subjected to accelerated P-8 aircraft loading. Saltwater concrete performance was found to be similar to freshwater concrete for all scenarios investigated. The overall conclusion was that saltwater can be used in place of freshwater for concrete airfield pavement construction and repair for short- to medium-term use (1–2 yr) with no meaningful impact to mission requirements.

29 May 2024

Finite Element, Petrographic, and Mechanical Analyses of Field-Cored Concrete Fairlead Beam Anchor Rods from Luke Air Force Base

Abstract: The fairlead beam is used to accomplish installation of the Barrier Arresting Kit 12 energy absorber for setback aircraft arresting system (AAS) installations at permanent operating facilities. Typical fairlead beams are affixed to a Portland cement concrete (PCC) foundation pad by a series of anchor assemblies made up of steel anchor rods set in grout inside galvanized pipe sleeves. US Air Force Civil Engineering Center (AFCEC) subject matter experts have identified a pattern of premature failures in these steel anchor assemblies when they are nondestructively inspected during AAS overhauls. The US Army Engineer Research and Development Center was tasked by AFCEC to investigate potential reasons for these premature failures. This report outlines methods and results of a finite element analysis of the anchorage, a visual and petrographic analysis of field-cored PCC anchor rods from Luke Air Force Base, and a mechanical analysis of specimens taken from the anchor rods within the PCC cores. Multiple modes of PCC distress were observed, and corrosion was evident in and around the anchor assemblies. Mechanical testing of specimens from the anchor rods indicated that an inferior grade of steel was used to fabricate these particular assemblies. Finally, observed deviations from design intention are discussed.

3 Jan 2024

Residual Strength of a High-Strength Concrete Subjected to Triaxial Prestress

Abstract: This study investigates simplified mechanical loading paths that represent more complex loading paths observed during penetration using a triaxial chamber and a high-strength concrete. The objective was to determine the effects that stress-strain (load) paths have on the material’s unconfined compressive (UC) residual strength. The loading paths included hydrostatic compression (HC), uniaxial strain in compression (UX), and uniaxial strain load biaxial strain unload (UXBX). The experiments indicated that the load paths associated with nonvisible microstructural damage were HC and UX—which produced minimal impact on the residual UC strength (less than 30%)—while the load path associated with visible macro-structural damage was UXBX, which significantly reduced the UC strength (greater than 90%). The simplified loading paths were also investigated using a material model driver code that was fitted to a widely used Department of Defense material model. Virtual experiment data revealed that the investigated material model overestimated material damage and produced poor results when compared to experimental data.

15 Sep 2022

Evaluation of a Prototype Integrated Pavement Screed for Screeding Asphalt or Concrete Crater Repairs

Abstract: Finishing, or screeding, the hot mix asphalt or rapid-setting concrete surface of a crater repair is important for rapid airfield damage recovery (RADR) since it determines the aircraft ride surface quality. The objective of RADR repairs is to expediently produce a flush repair, defined as ±0.75 in. of the surrounding pavement surface, with minimal logistical and personnel burden. Multiple screeds were previously evaluated; the most recent project proposed a prototype design of a telehandler-operated integrated screed for both small and large repairs using asphalt or concrete. This project’s objective was to finalize the prototype design and fabricate and test the prototype RADR screed. The prototype RADR screed was successful for small repairs (8.5×8.5 ft). Large repairs (30×30 ft) were generally successful with modest repair quality criteria (RQC) issues being the only notable deficiencies. Large concrete repair RQC issues were attributed to plastic formwork movement, and large asphalt repair RQC issues were attributed to compaction issues or improper roll-down factors. Methods to mitigate these factors were investigated but should be further evaluated. Overall, the RADR screed was successful from technical perspectives but, functionally, is 600-800 lb overweight. Weight reduction should be considered before entering production.

20 Aug 2021

Crevice Corrosion and Environmentally Assisted Cracking of High-Strength Duplex Stainless Steels in Simulated Concrete Pore Solutions

Abstract: This paper presents a study of crevice corrosion and environmentally assisted cracking (EAC) mechanisms in UNS S32205 and S32304 which were cold drawn to tensile strengths of approximately 1300 MPa. The study utilized a combination of electrochemical methods and slow strain rate testing to evaluate EAC susceptibility. UNS S32205 was not susceptible to crevice corrosion in stranded geometries at Cl- concentrations up to 1.0 M in alkaline and carbonated simulated concrete pore solutions. UNS S32304 did exhibit a reduction in corrosion resistance when tested in a stranded geometry. UNS S32205 and S32304 were not susceptible to stress corrosion cracking at Cl- concentrations up to 0.5 M in alkaline and carbonated solutions but were susceptible to hydrogen embrittlement with cathodic overprotection.

6 Aug 2021

Print Time vs. Elapsed Time: A Temporal Analysis of a Continuous Printing Operation for Additive Constructed Concrete

Abstract: In additive construction, ambitious goals to fabricate a concrete building in less than 24 hours are attempted. In the field, this goal relies on a metric of print time to make this conclusion, which excludes rest time and delays. The task to complete a building in 24 hours was put to the test with the first attempt at a fully continuous print of a structurally reinforced additively constructed concrete (ACC) building. A time series analysis was performed during the construction of a 512 ft2 (16’x32’x9.25’) building to explore the effect of delays on the completion time. This analysis included a study of the variation in comprehensive layer print times, expected trends and forecasting for what is expected in future prints of similar types. Furthermore, the study included a determination and comparison of print time, elapsed time, and construction time, as well as a look at the effect of environmental conditions on the delay events. Upon finishing, the analysis concluded that the 3D-printed building was completed in 14-hours of print time, 31.2- hours elapsed time, a total of 5 days of construction time. This emphasizes that reports on newly 3D-printed constructions need to provide a definition of time that includes all possible duration periods to communicate realistic capabilities of this new technology.

4 May 2021

Laboratory characterization of Cor-Tuf Baseline and UHPC-S

Abstract: This experimental effort is part of a larger program entitled Development of Ultra-High-Performance Concrete Tools and Design Guidelines. This program operates in accordance with an agreement concerning combating terrorism research and development between the United States of America Department of Defense and the Republic of Singapore Ministry of Defence. The objective of the program is to develop a better understanding of the potential benefits that may be achieved from the application of ultra-high-performance concrete (UHPC) materials for protective structures. The specific effort detailed in this report will provide insight into laboratory-scale mechanical properties of Cor-Tuf and a proprietary material termed UHPC-Singapore (UHPC-S).

22 Apr 2021

Rapid Airfield Damage Recovery Next Generation Backfill Technologies Comparison Experiment : Technology Comparison Experiment

Abstract: The Rapid Airfield Damage Recovery (RADR) Next Generation Backfill Technology Comparison Experiment was conducted in July 2017 at the East Campus of the U.S. Army Engineer Research and Development Center (ERDC), located in Vicksburg, MS. The experiment evaluated three different crater backfill technologies to compare their performance and develop a technology trade-off analysis. The RADR next generation backfill technologies were compared to the current RADR standard backfill method of flowable fill. Results from this experiment provided useful information on technology rankings and trade-offs. This effort resulted in successful crater backfill solutions that were recommended for further end user evaluation.

15 Jan 2020

PUBLICATION NOTICE: Laboratory Characterization of Alkali-Silica Reaction Susceptibility of Aggregates for Charleroi Lock and Dam, Monongahela River Project

 Link: http://dx.doi.org/10.21079/11681/35118Report Number: ERDC/GSL TR-19-52Title: Laboratory Characterization of Alkali-Silica Reaction Susceptibility of Aggregates for Charleroi Lock and Dam, Monongahela River ProjectBy Monica A. RamseyApproved for Public Release; Distribution is Unlimited December 2019Abstract:  The purpose of this study was to