Reinforcement of Old Steel Bars Through Fibers, and its Effects on the Mechanical Properties

Abstract

The corrosion causes a harmful loss of the mechanical properties of the reinforcing steel, strength, ductility, and service life are reduced consequently. The paper focuses on the viability of reinforcing the naturally corroded steel bars, aged 45-50 years that have been extracted out of a demolition bridge and restoring them using externally bonded carbon fiber (CF) package. This work is in contrast to the majority of other research in which artificial corrosion is employed that may not relate to the natural process that occurs over extended periods, as in real world service. A DMAIC Six Sigma model (define, measure, analyse, improve, control) was used. Three sets of specimens were tested conducting a tensile and bending test of a steel bar that was new, naturally corroded old bars, and corroded bars reinforced utilizing CF. The corroded bars experienced great losses in properties compared to standards where the yield strength, ultimate strength, tensile strength, and elongation of the bar reduced by 17.62, 20.19, and 27.52, and 15.76 respectively, and the diameter reduced by 6.62. CF-wrapping resulted in significant enough gains of yield strength by 40.57%, ultimate strength by 26.60%, tensile strength by 8.47%, elongation by 39.58%, and nominal diameter by 13.83%. Every bending piece sample passed bending test These results indicate that reinforcement imbibed by CF wrapping can be an efficient method of recovery of long-term corroded reinforcement, implying its prospective preeminence as a sustainable type of reinforcement repairing within the framework of quality enhancement.

Key Words: Corrosion, Yield strength, ultimate strength, tensile strength, mechanical properties before and after implementation of Six Sigma