- 學位論文
電化學技術在鋼筋腐蝕檢測之比較研究
Comparsion of the Electrification Analytic Techniques for Corrosion Detection of Steel Bars
摘要
本研究係採用電化學法來量測腐蝕電位、混凝土電阻係數和腐蝕電流密度，並利用直流電流加速腐蝕，然後使用GECOR 8腐蝕量測儀，量測不同腐蝕程度鋼筋之腐蝕電位值、混凝土電阻係數及腐蝕電流密度，並與CANIN腐蝕探測儀量測之腐蝕電位值作比較。在量測結束後，將混凝土中之鋼筋取出，以重量損失法計算鋼筋損失量及腐蝕速率，並與儀器量測值作比較。 試驗結果顯示，由各儀器量測的腐蝕電位隨著時間增加有上升的趨勢，與鋼筋外露越接近的測點，所測得的腐蝕電位就可能越低。GECOR 8探頭B量測腐蝕電位值與CANIN較為接近，而探頭A和探頭C較為接近且較低，由上述可知探頭B較為正確。探頭B用於量測混凝土電阻係數較為準確。探頭A量測腐蝕電流密度偏低而顯示較不正確。本研究結果顯示，加速腐蝕試驗中，鋼筋腐蝕量與通電量相關性良好，其迴歸關係式Wloss=0.32Q+4.6，R2為0.86。腐蝕電位法檢測鋼筋腐蝕狀態之可行性甚差，混凝土電阻係數之量測結果為反應保護層的混凝土品質，而並非鋼筋之腐蝕狀態，因此與鋼筋腐蝕量之相關性甚小。重量損失法之電流密度icorrW對探頭C測得電流密度icorrC之相關是良好的，其迴歸式icorrW=1.24icorrC+5.5，R2為0.72，式中之截距5.5 μA/cm2可視為鋼筋外露部份之腐蝕電流密度估計值。
並列摘要
In the study, the electrification analytic technique was used to measure corrosion potential, concrete resistivity and corrosion current density, and then a direct current device was utilized to accelerate corrosion. The GECOR 8 corrosion rate meter was used to measure corrosion potential, concrete resistivity, and corrosion current density in different level of corrosion steel bars. The next values were then compared with the corrosion potential measured by the CANIN corrosion instrument. After the measurements, steel bars were taken from concrete and to calculate their losses by the weight loss method. The results were then compared with the measured values. The test results show that, the measured corrosion potential by the apparatus basically increases with time. The point closer to the exposure of reinforcing bar probably has lower measured corrosion potential. The corrosion potential measured by detector B of GECOR 8 is closer to that by CANIN, and those by detector A and detector C are lower and close to each other. Therefore, the values of detector B may be more accurate. The concrete resistivity measured by detector B is more accurate than that by detector C. The corrosion current density detector A is too lower than that by detector C and is not accurate. The results also show that, in the corrosion-accelerated tests, the amount of steel corrosion is well correlated with the electricity amount. The regression equation is Wloss=0.32Q+4.6, R2 is 0.86. The feasibility of using corrosion potential method to measure steel corrosion is bad. Concrete resistivity is to reflect the quality of concrete in protective layer, not the steel corrosion. Therefore, its correlation with steel corrosion is small. The corrosion current density by the weight loss method icorrW is well correlated with that by detector C icorrC. The regression equation is icorrW=1.24icorrC+5.5, R2 is 0.72. The intercept of the equation 5.5 μA/cm2 can be treated as the estimated corrosion current density for the exposed part of steel bar.