Influence of Low Strain Rate on Uniaxial Tensile Test Parameters of Reinforcing Steel Bars

ABSTRACT
This study investigates experimentally the uniaxial stress-strain behavior of reinforcing steel bars under
various low strain rates, quasi-static from 0.001 12 s-1 to 0.006 70 s-1. The main objective of these tests was to
give an indication of the effect of the low strain rate variation on the uniaxial, monotonic, stress-strain,
elongation-strain, section reduction-strain curves of reinforcing steel bars. The results of the tensile tests
indicate that the yield strength and the ultimate tensile strength of reinforcing steel bars increase as the strain
rate increases; while the elongation and section reduction of reinforcing steel bars do not appear to be
substantially affected by the low strain rate variation. It was also observed that the smaller reinforcing steel bars
were more affected by low strain rate variation, although sometimes inconsistently, than the relatively bigger
ones. Thus, one should be more precautious while testing smaller reinforcing steel bars. Furthermore, a new
regression formula is proposed for both yield strength and ultimate tensile strength with an “R squared” of 80%.
This formula may be used as a means by which some quick verifications and checking may be done.