Experimental Investigation of Various Corroded Metal Materials Used in Building Structures

Abstract

The study of corroded metal materials in building structures is the basis for analyzing and evaluating the residual bearing capacities of existing structures. In this study, the corrosion behaviors and residual properties of two types of low-alloy steel and a 6061-T6 aluminum alloy were investigated under different corrosion times in an acetic acid spray environment. Scanning electron microscopy (SEM) and three-dimensional (3D) laser scanning were performed. Uniaxial tensile tests were conducted on the three metal materials with different corrosion levels. The test results showed that the corrosion rate of the aluminum alloy increased with corrosion time, and the corrosion rates of the low-alloy steels decreased with corrosion time. The pitting of the low-alloy steels was shallow and wide; the pitting of the 6061-T6 aluminum alloy was narrow and deep. Characteristic parameters are proposed for the pitting morphologies of the low-alloy steels. The corrosion depths of the pitting were more inclined toward a generalized extreme value distribution. Simplified models and evaluation indexes were defined for the stress-strain relationships of the three materials. The two types of low-alloy steel were reduced to 60% of their original engineering strength, and the engineering strength of the aluminum alloy was reduced to 85%. Methods are proposed for evaluating the residual mechanical properties of different structural materials with different corrosion behaviors.