THESIS
2011
xiv, 88 p. : ill. ; 30 cm
Abstract
In this thesis, the combined use of Fiber Reinforced Cenmentitious Composite (FRCC) and Fiber Reinforced Plastic (FRP) in two applications is studied. First, the FRCC plate has been investigated as an anchor to improve the performance of FRP sheets on concrete members. Second, the high-strength fiber reinforced cementitious composites (HSFRCC) has been studied as a joining material for permanent formwork elements with protruding GFRP that will be embedded in the joint....[
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In this thesis, the combined use of Fiber Reinforced Cenmentitious Composite (FRCC) and Fiber Reinforced Plastic (FRP) in two applications is studied. First, the FRCC plate has been investigated as an anchor to improve the performance of FRP sheets on concrete members. Second, the high-strength fiber reinforced cementitious composites (HSFRCC) has been studied as a joining material for permanent formwork elements with protruding GFRP that will be embedded in the joint.
For the first application, to increase the bond and deformation capabilities of FRP sheets employed in the strengthening of concrete members, the precast FRCC plate is glued on top of the FRP sheets. In order to measure the improvement in terms of ultimate load and deformation capacity and to study the failure mechanisms around the anchored area, the direct shear bond test is performed on concrete prisms with bonded FRP. Several sets of tests have been carried out with anchoring plates of different FRCC compositions and lengths. Comparison with the control sample shows that the installation of FRCC plate can significantly increase both the bond and deformation capacities (by up to 100%). Based on the shear bond test, two types of FRCC plate materials were found to be particularly effective and selected for strengthening of beam members to be tested under four point bending. Comparison with control members (without anchor) and those with conventional U-shape FRP anchors indicates that both the ultimate load and central deflection can be improved by the new anchoring method.
The second application is related to the development of permanent formwork for durable concrete structures., Formwork elements, fabricated with pseudo-ductile cementitious composites (PDCC) and embedded glass fiber reinforced polymer (GFRP) reinforcement, need to be effectively joined together. A novel jointing method, involving the embedment of GFRP in high-strength fiber reinforced cementitious composites (HSFRCC), is proposed. Direct pull-out test is carried out to investigate the bonding capacity between the HSFRCC and GFRP reinforcement. From the experimental data, interfacial parameters are extracted for calculating the required embedded length of GFRP bars to ensure sufficient bonding capacity. According to the test results, the required embedded length of GFRP bars is about 21d (where d is the diameter of GFRP bar). Beam members with joined and monolithic PDCC formwork are prepared and tested under four point bending. In the presence of the joint in the formwork, the load capacity decreases by only 5%. Also, the ultimate load is higher than the value obtained from conventional reinforced concrete design calculations. The feasibility of the joining method for practical applications is hence verified.
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