Tensile Test of Steel for the Reinforcement of Concrete

Introduction

Reinforced concrete is a general material in the construction and civil engineering fields, and is used in all types of structures, including buildings, tunnels, and bridges. The ribbed bars used as reinforcing materials for reinforced concrete have a shape with surface rib, which improve bonding with concrete or mortar by providing a larger surface area than that of round steel bars with a smooth surface, and also strengthen resistance against pull-out (slipping). Strength evaluation is important because standard values for tensile strength, proof strength, and other mechanical properties are specified depending on the type of ribbed bar. Tensile testing method for ribbed bars is described in JIS G 3112 : 2010 “Steel bars for concrete reinforcement.” However, measurement in accordance with JIS G 3112 is difficult with the contact-type extensometers in general use, which have a fixed gauge length, because the standard requires that the gauge length of test pieces must be changed depending on the designation (diameter) of ribbed bars. Here, JIS G 3112: 2010-compliant tensile tests of ribbed bars with two different designations were conducted using a Shimadzu TRViewX non-contact digital video extensometer, which enables free selection of the gauge length.

October 27, 2020 GMT