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Title |
Cracking Behavior of Reinforced Concrete Structures due th Reinforcing Steel Corrosion
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Authors |
오병환 ; 김기현 ; 장승엽 ; 강의영 ; 장봉석 |
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Keywords |
철근부식; 철근부식팽창; 임계부식량; 균열; 콘크리트피복균열; corrosion of steel bar; expansion of steel; critical corrosion; concrete cover cracking |
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Abstract |
Corrosion products of reinforcement in concrete induce pressure to the adjacent concrete due to the expansion of steel. This expansion causes tensile stresses around the reinforcing bar and eventually induces cracking through the concrete cover The cracking of concrete cover will adversely affect the safety as well as the service life of concrete structures. The purpose of the this study is to examine the critical corrosion amount which causes the cracking of concrete cover. To this end, a comprehensive experimental and theoretical study has been conducted. Major test variables include concrete strength and cover thickness. The strains at the surface of concrete cover have been measured according to the amount of steel corrosion. The corrosion products which penetrate into the pores and cracks around the steel bar have been considered in the calculation of expansive pressure due to steel corrosion. The present study indicates that the critical amount of corrosion, which causes the initiation of cracking, increases with an increase of compressive strength. A realistic relation between the expansive pressure and average strain of corrosion product layer in the corrosion region has been derived and the representative stiffness of corrosion layer was determined. A concept of pressure-free strain of corrosion product layer was introduced to explain the relation between the expansive pressure and corrosion strain. The proposed theory agrees well with experimental data and may be a good base for the realistic durability design of concrete structures.
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