Title: Mechanical and bond properties of Grade 2205 duplex high-strength stainless steel strand
Date Published: July - August 2021
Volume: 66
Issue: 4
Page Numbers: 66 - 81
Authors: Anwer Al-Kaimakchi and Michelle Rambo-Roddenberry
https://doi.org/10.15554/pcij66.4-01

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Abstract

The sustainability of concrete structures can be enhanced by using duplex high-strength stainless steel (HSSS) strands, due to their high corrosion resistance, in place of conventional carbon steel strands. This paper experimentally evaluates mechanical and bond properties of 0.6 in. (15.2 mm) diameter HSSS strands. Ten strands each from two spools were tensile tested to failure. The strands had lower yield and ultimate stresses, ultimate strain, and elastic modulus than carbon steel strands, and they met the minimum mechanical properties specified in the recently published ASTM A1114 Standard Specification for Low-Relaxation, Seven-Wire, Grade 240 [1655], Stainless Steel Strand for Prestressed Concrete. HSSS strands exhibit nonlinear behavior beyond the elastic modulus. A stress-strain equation is proposed for 0.6 in. diameter HSSS strands, satisfying ASTM A1114 and in good agreement with experimental results. Five 0.6 in. diameter HSSS strands were tensile tested using standard chuck devices. The mechanical properties within the elastic region were not significantly affected by the use of chuck devices; therefore, chuck devices were deemed acceptable for use in the casting yard. The study was limited to straight strands. Six 0.6 in. diameter HSSS strands were tested for bond following ASTM A1081 Standard Test Method for Evaluating Bond of Seven-Wire Steel Prestressing Strand. The minimum and average experimental pullout values were 15.80 kip (70.3 kN) and 17.88 kip (79.5 kN), respectively, which were 23.4% and 19.8%, respectively, greater than the minimum recommended values calculated using the PCI Strand Bond Task Group equation.