![]() ![]() The results obtained from the study show that UPV decreases linearly with increase in degree of corrosion and corrosion-induced cracks (surface cracks). A UT device with two 54 kHz transducers was used to measure ultrasonic pulse velocity (UPV) of cement mortar, uncorroded and corroded reinforced cement mortar specimens, utilizing the direct transmission method. This study presents an experimental investigation of quantifying degree of corrosion of steel rebar inside cement mortar specimens using ultrasonic testing (UT). Traditional corrosion monitoring methods such as half-cell potential and linear polarization resistance can only detect the presence of corrosion but cannot quantify it. Owusu Twumasi, Jones Le, Viet Tang, Qixiang Yu, TzuyangĬorrosion of steel reinforcing bars ( rebars) is the primary cause for the deterioration of reinforced concrete structures. ![]() Quantitative sensing of corroded steel rebar embedded in cement mortar specimens using ultrasonic testing The results also indicate that the threshold temperatures of passivation for the oxide-skin rebar and the rusty-skin rebar are 37Â☌ and 20Â☌, respectively. The rusty-skin rebar exhibits the highest corrosion rate because crevice corrosion can accelerate the corrosion of the steel rebar, particularly at high temperature. ![]() Temperature has the greatest effect on the rusty-skin rebar and least effect on the polished steel rebar, because of cracks and crevices on the mill scale on the steel rebar's surface. Our results show that the passivation properties of all the surface types decrease with the increase of temperature. These measurements identified three kinds of surfaces: polished, oxide skin, and rusty skin. To study the effect of temperature on the passivation properties of steel rebar under different surface conditions, we conducted scanning electron microscopy (SEM) observations and electrochemical measurements, such as measurements of the free corrosion potential and polarization curves of HPB235 steel rebar. Steel rebar normally forms an oxide or rusty skin before it is embedded into concrete and the passivation properties of this skin will be heavily influenced by temperature. ![]() Effect of temperature on the passivation behavior of steel rebarĬhen, Shan-meng Cao, Bei Wu, Yin-shun Ma, Ke ![]()
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