RC Slabs Repaired and Strengthened by Alumina/Polymer Mortar and Prestressing Strands in the Tension Zone: Experimental Investigation Under Static and Fatigue Loadings
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While the extent of repair and rehabilitation of existing old concrete structures is rapidly increasing, a vast number of repaired and rehabilitated structures do not function properly during their remaining service life. Especially in the case of using heterogeneous repair materials, it is very important to maintain the bonding performance between materials and to prevent the interface failure under static and fatigue loads. This paper focuses on the experimental investigation of reinforced concrete (RC) slabs, repaired and reinforced with an alumina/polymer (AP) mortar and a prestressing (PS) strand in the tension zone, under static and fatigue loadings. The variables in this experimental study were the space of strengthening, the number of strands, and AP mortar thickness. Attention is concentrated on the overall load-carrying capacity, deflection, strains of reinforcing bars, and the efficiency of repaired and reinforced RC slabs. Test results showed that the deflection of the repaired and reinforced RC slabs was approximately 40% lower than that of control RC slabs. The initial and horizontal cracking loads of a RC slab with an AP mortar of thickness 30 mm in the static test were approximately the same as those of a RC slab with a 20-mm-thick one. In the fatigue test, the deflection, the strain of reinforcing bars at the midspan, and the maximum shear stress of the repaired and strengthened RC slab were about 40~70% lower than those of the control RC slab. Therefore, it can be concluded that RC slabs with an AP mortar and PS strands have a good strengthening efficiency under both static and fatigue loadings, thanks to the high bonding capacity of the AP mortar.
Keywordsrepaired and strengthened RC slab AP mortar PS strand static and fatigue load bonding capacity
This work was supported by the Postdoctoral Research Program of Sungkyunkwan University (2011).
- 3.G. Zanardo, H. Hao, Y. Xia, and A. Deeks, “Condition assessment through modal analysis of a run-on RC slab bridge before and after strengthening,” J. of Bridge Engineering, ASCE, (2006).Google Scholar
- 9.A. Ohta, T. Sugiyama, and T. Uomoto, “Study of dispersing effects of polycarboxylate-based dispersant on fine particles,” American Concrete Institute Special Publication SP-195, 211-227, (2000).Google Scholar
- 15.P. S. Rao and G. Mathew, “Behavior of externally prestressed concrete beams with multiple deviators,” Structural Journal, ACI, 93, No. 4, 7–8, (1996).Google Scholar
- 19.P. J. Heffernan, M. Erki, and D. L. DuQuesnay, “Stress redistribution in cyclically loaded reinforced concrete beams,” Journal of the American Concrete Institute, Structural, 101, No. 2, 261-268, (2004).Google Scholar
- 20.K. Yamada, H. Shima, and K. Haraguchi, “Effects of cyclic loading and time on the bond between a steel bar and concrete,” Proceeding of Japan Concrete Institute, 13, No. 2, 133-138, (1991).Google Scholar
- 21.Y. Taira, K. Suda, K. Aikawa, and T. Noguchi, “Cyclic fatigue loading experiment of connection joints in between pre-cast panels,” Transaction of Japan Society of Civil Engineers, 5, (2007).Google Scholar
- 25.ACI 440.3R-04, Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures, 20-22, (2004)Google Scholar