鋼材在模擬混凝土環境下之氫滲行為研究

Hydrogen Permeation Through Cathodically Protected Steel Membranes in Simulated Concrete Environment

本研究旨在探討外加陰極電流對模擬混凝土環境下之鋼材氫滲透的影響，以間接瞭解鋼材氫脆化的可能性。研究方法主要是藉由電化學氫滲透實驗來獲得試片之氫滲電流密度，試驗變數包括碳鋼之含碳量、外加陰極電流密度、陰極槽電解液以及水泥砂漿保護層之水灰比等因素。由研究結果顯示，無覆蓋水泥砂漿保護層的鋼片在3.5% NaCl溶液中，其氫滲電流密度會隨鋼材之含碳量降低及外加電流密度增加而變大；此外，陰極槽電解液為含3.5% NaCl之模擬混凝土孔隙水溶液（SPS），其氫滲電流密度較3.5% NaCl者高。有覆蓋水泥砂漿保護層的鋼片，其氫滲電流密度受水泥砂漿保護層水灰比的不同而改變，氫滲透行為較無保護層複雜。

The effects of an impressed cathodic current on the hydrogen permeation in iron membranes protected by cement-based composite materials were studied. The electrochemical hydrogen permeation technique was used to measure the hydrogen permeation current of the membranes. The main emphasis in this work was to investigate the factors that might affect hydrogen permeation through cathodically protected iron membranes with and without mortar cover. These included the effects of the carbon content of steel, impressed cathodic current density, cathodic electrolyte, and water/cement ratio. Experimental results shows that the hydrogen permeation current density for bare iron membranes immersed in 3.5% NaCl solution increased with decreasing carbon content and increasing cathodic current density. And the hydrogen permeation current density for the bare iron membranes immersed in a simulated cement pore solution (SPS) with 3.5% NaCl addition was higher than the one immersed in 3.5% NaCl solution. It appeared that the behavior of hydrogen permeation current density for the iron membranes covered with mortar was more complex than that without mortar-covered ones.