CFRP包覆鋼筋混凝土圓柱試體之鋼筋腐蝕膨脹應力量測與分析之研究

A Study on the CFRP Confine the Reinforced Concrete Cylinder Specimen to Measure the Swelling Stress of Steel Rebar Corrosion

文介紹利用實驗與力學分析求得鋼筋生銹體積膨脹造成之膨脹應力。本文內容共規劃了12個10cm（直徑）× 20cm（高度）的混凝土圓柱試體，試體內部埋置不同斷面尺寸之竹節鋼筋；並在鋼筋混凝土柱試體外分別包覆碳纖維強化高分子複合材料（Carbon Fiber Reinforced Plastics, CFRP），並且利用外加電流方法通電加速鋼筋混凝土圓柱試體內部之鋼筋腐蝕，進而造成混凝土圓柱試體爆裂。同時也在CFRP表面貼上應變計，來量測CFRP因鋼筋腐蝕圓柱試體而造成體積膨脹進而導致CFRP受力之應變。由於鋼筋是受到電流腐蝕產生膨脹應力，此應力無法以理論去計算；因此本文藉由有限元素分析軟體ANSYS來進行分析模擬，首先建立本實驗的圓柱試體分析模型，並在鋼筋處施以不同溫度的變化而使鋼筋產生膨脹應力，此目的為模擬鋼筋銹蝕造成之膨脹應力，此一膨脹應力造成圍束試體之碳纖維產生環向應變。然後，再依序建立各組試體鋼筋膨脹應力對應碳纖維應變的關係圖，最後再將實驗量測系統中所得的碳纖維複合材料破壞應變數據代入鋼筋膨脹應力對應碳纖維應變圖中，利用查圖法即可求出所對應鋼筋腐蝕造成的膨脹應力值。

In this paper, the experiment and finite-element analysis were used to obtain the swelling stress caused by the corrosion of steel rebar. Twelve reinforced concrete cylinder specimens with a dimension are 10 cm (diameter) × 20 cm (height) were built. These specimens were lay up by the different dimensions of rebar and confined by different layers of carbon fiber reinforced plastics (CFRP). And then we use the electrochemical method to accelerate the steel corrosion and to cause the reinforced concrete cylinder specimens blow out. Stain gauges were put on the surface of CFRP to measure the CFRP stain caused by the volumetric swelling because of steel rebar corrosion. It is not easy to calculate the swelling stress caused by steel rebar using theoretical methodology. Therefore, we proposed the finite-element analysis to model the experiment of the reinforced concrete cylinder specimen, and applied different temperature change to replace the swelling stress caused by the swelling stress of steel. The relationships between the stress of steel rebar and the strain of CFRP were obtained, and then we can easily find the swelling stress of steel caused by steel corrosion.