Monotonic and cyclic behavior of high strength reinforcing steel (HSRS) after high temperature exposure

Conventional reinforced concrete transportation structures in North America often use Grade 60 reinforcing steel with a yield stress of 60 ksi. The introduction of high strength reinforcing steel (HSRS) with higher yield strength in the reinforced concrete industry has led to many economic and workability advantages such as construction time saving, reduced labor cost and steel consumption which in turn alleviates congestion of reinforcement, savings in transportation and deliveries that finally results in lower carbon emission. Despite these benefits, many states, including those in Region 6, have not widely adopted the use of higher strength reinforcing steels in practice due to lack of knowledge and comfort level with implementing new technologies and techniques, and the serviceability and durability concerns. In addition, bridge surveys among 18 states have shown that fire has caused more bridge collapses than earthquakes. In general, there are three common types of ASTM steel bars that are produced with yield stresses above 60 ksi: ASTM A615, ASTM A706 and ASTM A1035 (CL, CM and CS based on carbon and chromium content). Given the lower ductility of HSRS rebars compared to conventional reinforcement along with the lack of knowledge on different types of HSRS and their behavior when exposed to elevated temperatures, studying the behavior of HSRS after high temperature exposure is deemed to be necessary. In this study, four different tests will be conducted on three different ASTM reinforcement (A615, A706, and A1035): monotonic and cyclic tensile tests (high strain low cycle), pullout and endbeam bond tests. Each test shall be performed at both ambient and elevated temperatures. After the test, each specimen will be analyzed using Energy dispersive X-Ray (EDX) and scanning electron microscopy (SEM) to investigate the possible change in material composition and failure analysis of fracture surfaces, respectively. The results will be reported and compared with the previous studies on conventional and HSRS reinforcements. The results of this study will allow states and authorities to make more informed decisions based on the enhanced knowledge on the behavior of HSRS in reinforced concrete transportation structures such as bridges.

• Supplemental Notes:
  • 22STUTA21

Language

• English

Project

• Status: Active
• Funding: $106000
• Contract Numbers:

  69A3551747106

• Sponsor Organizations:

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Managing Organizations:

  Transportation Consortium of South-Central States (Tran-SET)

  Louisiana State University
  Baton Rouge, LA  United States  70803
• Project Managers:

  Mousa, Momen

• Performing Organizations:

  University of Texas at Arlington

  Box 19308
  Arlington, TX  United States  76019-0308
• Principal Investigators:

  Jalali, Himan

• Start Date: 20220401
• Expected Completion Date: 0
• Actual Completion Date: 0
• USDOT Program: University Transportation Centers Program

Subject/Index Terms

• TRT Terms: Bond strength (Chemistry); Failure analysis; High temperature; Reinforcing steel; Tensile strength
• Subject Areas: Bridges and other structures; Highways; Materials; Safety and Human Factors;

Filing Info

• Accession Number: 01844948
• Record Type: Research project
• Source Agency: Transportation Consortium of South-Central States (Tran-SET)
• Contract Numbers: 69A3551747106
• Files: UTC, RIP
• Created Date: May 9 2022 6:15AM