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Corrosion Damage of Reinforcement Embedded in Reinforced Concrete Slab

Gao, Zhicheng
http://rave.ohiolink.edu/etdc/view?acc_num=akron1478174479305336

Abstract Details

2016, Doctor of Philosophy, University of Akron, Civil Engineering.
Corrosion of reinforcements embedded in concrete is a worldwide problem that affects numerous reinforced concrete (RC) structures. While corrosion has always been problematic since the beginning of mining and refinery of metals, corrosion in RC structures only gained research attention during the 1960s and 1970s, following widespread use of de-icing salts on highways in United States. Since then, research has been undertaken worldwide to address corrosion issues. In this dissertation, an experimental study was conducted to characterize the structural behavior of reinforced concrete slabs subjected to accelerated corrosion in the lab. In order to make the experimental condition similar to the real service environment, the test specimens were introduced with pre-existing cracks and sustained loading was applied during the corrosion process. Accelerated corrosion of tensile steel reinforcements in RC slabs was facilitated by an accelerated corrosion process. Three different test conditions were induced in the corrosion test program: specimens without pre-existing cracks and sustained loading, specimens with pre-existing cracks but no sustained loading, and specimens with pre-existing cracks and sustained loading. In addition, different wetting and drying cycles were incorporated in the corrosion process. Expansion of longitudinal cracks along the tensile reinforcements and transverse cracks crossing the tensile reinforcements were recorded during the corrosion testing. Multiple desired corrosion levels-from low level (1%) to high level (20%)- were applied to different specimens. The gravimetric metal loss along the longitudinal direction of reinforcements was measured after the bending test. An empirical relationship was developed based on the representative specimens corroded with pre-existing cracks and sustained loading conditions for all desired corrosion levels. The epoxy-coated reinforcements and polypropylene (PP) fibers were used during casting experimental specimens to assess their corrosion resistance properties. By using the constant electric current, 10 and 20% desired corrosion levels were applied to most specimens, and 40% desired corrosion level was also applied to several test specimens with PP fibers additives to simulate the severe corrosion condition. The surface defects of epoxy-coated reinforcements and two different quantity ratios of PP fibers - 4.5 kg/m^3 and 6 kg/m^3 were considered in this study. The ultimate capacity of corroded specimens was tested after corrosion process. The average metal loss, the reduced yield strength of corroded reinforced bars and the effective cross section of the specimens can accurately predict the theoretical ultimate capacity loss compared with testing results. The critical inner expansive pressure from XFEM was applied to the developed numerical model to predict the cracking time of the cover concrete, which is defined as the severability limitation of the corroded RC structures. The proposed prediction model had been validated by comparing with the existing experiment data of uniform corrosion condition and the results show that the accuracy of developed model was acceptable to predict the serviceability of reinforced structures with corrosion damage. The effect of non-uniform corrosion condition on cracking pressure from XFEM and cracking time using developed prediction model was discussed.
Robert Liang (Advisor)
Anil Patnaik (Advisor)
Zhe Luo (Committee Member)
Yalin Dong (Committee Member)
En Chen (Committee Member)
160 p.
Civil Engineering
corrosion; reinforced concrete; cracks; metal loss

Recommended Citations

Citations

  • Gao, Z. (2016). Corrosion Damage of Reinforcement Embedded in Reinforced Concrete Slab [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1478174479305336

    APA Style (7th edition)

  • Gao, Zhicheng. Corrosion Damage of Reinforcement Embedded in Reinforced Concrete Slab. 2016. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1478174479305336.

    MLA Style (8th edition)

  • Gao, Zhicheng. "Corrosion Damage of Reinforcement Embedded in Reinforced Concrete Slab." Doctoral dissertation, University of Akron, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1478174479305336

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Akron and OhioLINK.