Bridge Decks Strengthened with Near-Surface Mounted Bars Embedded in Cement-Based Grout
نویسنده
چکیده
Near-surface mounted (NSM) bars have been used for flexural strengthening of reinforced concrete members. The data available on this type of reinforcement technique are limited and typically, the bars or strips are embedded using an epoxy. Long term durability, abrasion resistance, and compatibility of the repair are important issues with this type of repair. One untested option for embedding the FRP bars into existing concrete is by using a Portland cement based grout. Laboratory specimens designed to represent bridge deck segments were strengthened using NSM bars embedded in a cement grout. Seven bridge deck segments were tested in flexure using three different types of NSM bars (GFRP, CFRP and MMFX bars) and two types of adhesive/filler materials (epoxy and cement based grout). The results indicate a significant improvement in the flexural capacity of all specimens strengthened using NSM bars. The epoxy adhered NSM specimens improved the most with an increase in the flexural capacity from 1.4 to 1.8 times the capacity of the control. The cement based grout adhered specimens had improved capacities of 1.3 to 1.4 times the capacity of the control. The failure mode of the epoxy specimens was concrete failure (concrete crushing or concrete shear failure) while the Portland cement grout specimens all had failure modes associated with bond (bar slippage or grout splitting) at the interface between the reinforcing bars and the Portland cement grout.
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