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Srikanth Marchetty_ Dissertation.pdf (11.56 MB)

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REDUCTION OF TRANSVERSE CRACKING IN STRUCTURAL SLAB BRIDGE DECKS USING ALTERNATIVE MATERIALS

Marchetty, Srikanth
http://rave.ohiolink.edu/etdc/view?acc_num=akron1525448493648127

Abstract Details

2018, Doctor of Philosophy, University of Akron, Civil Engineering.
Cracking on decks is one of the major concerns for bridges located all over the United States, affecting the durability and service life of the bridge. The CSS (Continuous Span Structural Slab) bridges, without stringers and are the most commonly used bridges in counties over the streams. Several CSS bridges in Ohio were surveyed to inspect crack widths on the bridge decks; and it was found that the crack widths over the negative moment regions were as wide as 0.125 inches. Such wide cracks exceed the recommended limit by ACI 224R-01 on bridges exposed to deicing salts by a factor of over 15. The permanently opened cracks act as pathways to the chlorides from the de-icing salts, allowing them to reach the reinforcement, causing aggressive environment around the embedded steel. This causes corrosion of the embedded reinforcing bars leading to severe section loss in steel. It was observed in the past, that epoxy-coated bars caused wider cracks compared to conventional black steel when used in reinforced concrete flexural applications. These wider cracks allow chlorides to penetrate the slab and directly attack the steel exposed due to the damage caused by epoxy coating during its handling. The corrosion of the epoxy coated bars leads to peeling off due to poor adhesion of the coating to the base steel. This causes a loss of bond with the surrounding concrete and loss in flexural capacity, which is of critical concern for the service life of the bridge. These cracks not only open and close under traffic loading, but widen over time due to the action of freeze-thaw effect and continuous fatigue due to vehicular loading. Experimental program was designed to reduce cracking using alternative reinforcing bars, with better bond characteristics as well better corrosion resistance. Prism tests with various corrosion resistant bars which include epoxy-coated bars, hot-dipped galvanized bars, stainless steel bars, CGR-UAR bars, MMFX bars revealed that epoxy coated bars caused wider cracks than all other bar types and prisms with CGR-UAE, MMFX bars showed smaller crack widths at same stress level. Flexural tests on slabs reinforced with corrosion-resistant bars revealed the same conclusions as that of prism specimens. The crack widths on prism and slab specimen were further reduced by using fiber reinforced concrete. Polypropylene fibers at a dosage of 10 lb/yd3 were added to the QC2 mix design to cast and test specimens with fibers. Corrosion tests on small-scale slabs were also performed to investigate the corrosion performance of these bars under accelerated corrosion and sustained load condition. Epoxy-coated bars with 5% defects showed highest flexural capacity loss compared to other bar types, but with 2.5% defects showed similar damage as that of slabs with black bars indicating no protection. Slabs with MMFX, stainless-steel bars showed less capacity loss. Addition of fibers improved the performance of the slabs subjected to accelerated corrosion by reducing the crack growth and the capacity loss.
Anil Patnaik, Dr. (Advisor)
Craig Menzemer, Dr. (Committee Member)
Ping Yi, Dr. (Committee Member)
Xiaosheng Gao, Dr. (Committee Member)
Nao Mimoto, Dr. (Committee Member)
323 p.
Civil Engineering
Cracking, Bridge, Deck, Concrete, Transverse, Structural Slab, Corrosion, Fatigue, Tension, Freeze Thaw, Fiber, Crack widths, Gergely and Lutz, ACI

Recommended Citations

Citations

  • Marchetty, S. (2018). REDUCTION OF TRANSVERSE CRACKING IN STRUCTURAL SLAB BRIDGE DECKS USING ALTERNATIVE MATERIALS [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1525448493648127

    APA Style (7th edition)

  • Marchetty, Srikanth. REDUCTION OF TRANSVERSE CRACKING IN STRUCTURAL SLAB BRIDGE DECKS USING ALTERNATIVE MATERIALS. 2018. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1525448493648127.

    MLA Style (8th edition)

  • Marchetty, Srikanth. "REDUCTION OF TRANSVERSE CRACKING IN STRUCTURAL SLAB BRIDGE DECKS USING ALTERNATIVE MATERIALS." Doctoral dissertation, University of Akron, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1525448493648127

    Chicago Manual of Style (17th edition)

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