Why does dry and wet cycle accelerate corrosion in reinforced concrete?
due to capillary action of moisture in voids create such problems
Eight reinforced concrete test specimens were designed and made according to the structural requirements of reinforced concrete members in the era of Republic of China for electrochemical accelerated corrosion test in order to analyze the critical corrosion depth of rebar of the Republican Period reinforced concrete structures in Jiangsu and Zhejiang Province when concrete cover is cracked due to rebar's corrosion expansion. The surface cracks distribution of the specimens was analyzed, and the test rusts from the specimens were compared with the natural rusts from the actual Republican Period reinforced concrete structures with the method of X-ray diffraction quantitative analysis. Results show that the cracks due to rebar's corrosion expansion occur on the projection line of the edge of rectangular rebar. The average value of the ratio of the critical corrosion depth and the width of the rectangular rebar was achieved as 0.021 for the actual Republican Period reinforced concrete structures.