鋼筋腐蝕檢測方法之比較研究

Comparison Studies on the Corrosion Detection Techniques of Reinforcement

黃幼丞(You-Cheng Huang)

指導教授 ： 吳志興

國立屏東科技大學/工學院/土木工程系所/碩士(2007年)

https://doi.org/10.6346/NPUST.2007.00040

摘要

本研究係採用電化學加速腐蝕的方法，將鋼筋導入直流電流，使鋼筋在短期間內達到腐蝕，然後使用GECOR 8腐蝕量測儀，量測鋼筋在不同腐蝕狀態下之腐蝕電位值、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，將混凝土試體之鋼筋取出，利用重量損失法計算腐蝕速率，並且探討腐蝕速率與各量測值之關係。本文亦探討量測穩定之腐蝕電位所需的灑水量及等候時間。
本試驗結果顯示，欲於64cm×60cm×15cm之試體量得一穩定電位值，在平均流量0.368 kg/sec下，所需的灑水時間約為90秒(即33 kg灑水量)。灑完水後，所需的等候時間約為150秒。於加速腐蝕試驗中，鋼筋腐蝕量與通電量相關性良好，其相關係數R2為0.96。本研究顯示，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鋼筋保護層之混凝土品質，而非鋼筋之腐蝕狀態，因此與鋼筋腐蝕量之相關性甚小。GECOR 8之探頭A無法檢測出鋼筋正確的腐蝕速率；將探頭C量測之腐蝕電流密度icorrC對重量損失法之腐蝕電流密度icorrW作迴歸分析得關係式icorrW=0.47icorrC+5.18，式中之截距5.18 μA/cm2可視為鋼筋外露部份之腐蝕電流密度估計值，而因鋼筋腐蝕不均勻導致探頭C之量測值約為重量損失法之2倍。

關鍵字

重量損失法 ； 腐蝕速率 ； 腐蝕電位 ； 混凝土電阻係數 ； 腐蝕電流密度

並列摘要

In the studies, an electrochemical technique was used to accelerate the corrosion of reinforcements by direct electric current to make reinforcements corrode in a short time period. The GECOR 8 corrosion rate meter was then used to measure the corrosion potential, concrete resistivity and corrosion current density of the reinforcements. The results were compared with the corrosion potential measured by the CANIN corrosion instrument. After the measurements, the reinforcements were taken out from concrete specimen to calculate the corrosion rate by the weight loss method. The relationships between the corrosion rate and the above measurement results are discussed. The studies also discuss the required volume of pre-wetting water and waiting time for obtaining a stable corrosion potential value in the measurements.
The test results showed that, to obtain a stable measurement value of corrosion potential in 64cm×60cm×15cm specimen, the required sprinkling time of pre-wetting water with an average flow 0.368 kg/sec is 90 seconds (i.e. 33 kg in volume). After sprinkling, the required waiting time is 150 seconds. The corrosion weight is very well correlated the electric quantity. The correlation coefficient R2 is 0.96. The studies show that, the feasibility of detecting corrosion by the potential method is very poor. The measurementresults of concrete resistivity are to reflect the quality of reinforcement concrete cover, not the reinforcement corrosion state, so that, their correlation with corrosion weight is very little. The corrosion rate can’t be correctly measured by sensor A of GECOR 8. The regression analysis of the corrosion current density measured by sensor C icorrC versus that by the weight loss method icorrW gives the equation icorrW=0.47icorrC+5.18, where the intercept 5.18 μA/cm2 can be treated as an estimate for the corrosion current density of the uncover part of each reinforcement. And due to non-uniform corrosion on the reinforcements, the measurement values by sensor C is about 2 times of that by the weight loss method.

並列關鍵字

Weight Loss Method ； Corrosion Rate ； Corrosion Potential ； Concrete Resistivity ； Corrosion Current Density

參考文獻

13.ASTM G1-03，2003，Standard Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens.

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18.Kouloumbi, N., Batis, G., 1992, “Chloride Corrosion of Steel Rebars in Mortars with Fly Ash Admixtures,” Cement and Concrete Composites, Vol. 14, No. 3, pp. 199-207.

21.Hope, B. B., Page, J. A., and Ip, A. K. C., 1986, “Corrosion Rate of Steel in Concrete,” Cement Concrete Research. Vol. 16, No. 5, pp 771-781.

23.Kouloumbi, N., Batis, G., and Pantazopoulou, P., 1995, “Efficiency of Natural Greek Pozzolan in Chloride-Induced Corrosion of Steel Reinforcement,” Cement, Concrete and Aggregates, Vol. 17, No. 1, pp. 18-25.