Tag: concrete
  • 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.
  • Pittsburgh District: Research takes regular ‘Conk Creet’ to next level of cold weather construction

    Engineers have developed and tested concrete mixtures to overcome all kinds of environmental demands, but one construction category has evaded engineers for centuries until now: cold weather.
  • ERDC leads advances in sustainable materials for military construction

    Climate change is a major priority for the Biden administration, which has set a goal to reach net zero emissions by no later than 2050. As the Army works to meet these goals and accomplish the objectives set in its own Climate Strategy, it has begun to focus more attention on one of its biggest emissions drivers: construction activities related to its vast inventory of buildings.
  • 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.
  • 23-052 USACE to rehabilitate and improve Russel Creek Canal

    WALLA WALLA, Wash. – This winter, the U.S. Army Corps of Engineers, Walla Walla District will begin a rehabilitation and improvement project on Russel Creek Canal. The canal, a part of the Mill Creek Flood Control Project, is located downstream of Bennington Lake and runs approximately one mile from the lake to Russel Creek.
  • Stronger, Lighter, More Durable: Ultra-High Performance Concrete is key to a more sustainable and modern infrastructure network

    As the U.S. Army Corps of Engineers (USACE) works to modernize the nation’s infrastructure, it does so at a time when existing infrastructure components are operating well past their original lifespans. In the case of many of the locks supporting inland navigation, new techniques and technologies are critical to make sure lock facilities – some built in the 1930s – continue operating for another 100 years or more.
  • 22-073 USACE and Mill Creek Flood Control Zone District sign Project Partnership Agreement

    Walla Walla, Wash. – The U.S. Army Corps of Engineers, Walla Walla District, and Mill Creek Flood Control Zone District signed a Project Partnership Agreement for the Mill Creek Section 205 Project on November 21.
  • 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.
  • FED personnel earn American Concrete Institute certification

    USAG HUMPHREYS, Republic of Korea — Far East District personnel took advantage of the American Concrete Institute certification offered by trainers from the U.S. Army Corps of Engineers Savannah District, Materials Testing Regional Technical Center of Expertise, and the USACE Engineering Research and Development Center, based in Vicksburg, Miss., Sept. 27 – Oct. 8.
  • 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.