Papers by Keyword: Atmospheric Exposure Test

Abstract: In this research, an evaluation method for the time-dependent corrosion depth of uncoated structural steel plates using an Fe/Ag galvanic couple atmospheric corrosion monitoring (ACM)-type sensor was proposed. This method was focused on environments with and without effects of rainfall and airborne sea salt. Atmospheric exposure tests were carried out on the uncoated carbon steel plates in four sites in which the environments varied widely as a function of rainfall and airborne sea salt. In addition to this, the corrosive environments of the skyward-and groundward-facing surfaces of the plates were monitored using the ACM sensors.

Abstract: The atmospheric corrosion behaviors of AZ80 magnesium alloy are investigated by exposure test in different testing sites. After four months exposure test, the corrosion morphologies and the component of the corrosion products were observed by the scanning electron microscopy (SEM) equipped with energy-dispersive analysis of X-ray (EDAX). The corrosion rates of AZ80 magnesium alloys were calculated by mass-loss. The results indicated that the corrosion resistance of AZ80 magnesium alloy in the sea environment is the worst. The corrosion degree of the back surface is worse than the front side. The corrosion products are mainly formed by carbonate, and contain small amount of chloride in most environments, while in Xishuangbanna and Jiangjin area contain a little sulfate.

Abstract: The corrosion environments of individual parts of members in a steel structure vary significantly. Therefore, efficient maintenance requires accurately evaluating these environments and predicting corrosion damage over time. This research focused on comprehensively evaluating the corrosive environment of each part of members in the structures based on the mean corrosion depth of uncoated steel plates mounted on the members. Atmospheric exposure tests were conducted in four exposure fields in which the environments varied widely as a function of rainfall and airborne sea salt. Based on the test results, a practical method of estimating the mean corrosion depth using the thickness of the corrosion-product layer on the mounted plates that does not require removal of the corrosion product is proposed. Furthermore, a method for estimating the time-dependence of corrosion depth for parts of the members after deterioration of the paint coating is proposed.

Abstract: Various maintenance problem has been reported according to the increase in service period of steel structures. It is difficult to examine and evaluate the corrosion problem and phenomena because of its uncertainty based on the environmental condition. Thus, the corrosion characteristics of the carbon steel were investigated to analyze the corrosion effect of carbon steel on the different atmospheric environments. The atmospheric exposure tests on uncoated carbon steel plates were conducted, to examine the corrosion phenomena and to obtain a fundamental corroded surface under different corrosion atmospheric environments. The corrosion characteristics of the carbon steel were compared depending on their different atmospheric environment and their exposure periods.

Abstract: To ensure the safety of steel structures, it is important to evaluate the time-dependent corrosion behavior. The purpose of this research is to develop a method of predicting time-dependence of the corrosion surfaces of uncoated weathering steel plates in various corrosive environments. Atmospheric exposure tests were carried out on the uncoated steel plates for 0.5, 1, 2 and 4-years in Okinawa Island, Japan. Spatial statistical analyses were carried out on the corrosion surfaces of the tested specimens. In addition to this, the time-dependence of the corrosion surfaces were simulated by the spatial statistical technique.

Abstract: The purpose of this research is to propose a method for evaluating the time-dependent corrosion behavior of carbon steel plates using an atmospheric corrosion monitor (ACM) corrosion sensor consisting of a Fe/Ag-galvanic couple. Atmospheric exposure tests were carried out on steel　plates for periods of 6, 12, and 24-months on the island of Okinawa in Japan. The Specimens were mounted on racks at angles of 0, 45 and 90 to the horizontal to obtain corrosion data in various corrosive environments. In addition, the environments of the skyward- and groundward-facing surfaces of the specimens were monitored using ACM sensors. The sensor outputs were recorded during the exposure tests.