Abstract
The Glass Fiber-Reinforced Polyurea (GFRPU) which is the composite by the elastic polyurea and milled glass fiber have the mechanical characteristics to enhance tensile strength as well as ductility. It must be reinforcement materials in repair and retrofit applications for strengthening structural capacity and has a merit of simple construction of spray coating to prevent the debonding from concrete surfaces unlike the existing strengthening methods such as Fiber-reinforced polymer (FRP) or steel plate. This work compares the improvement degree in load-carrying capacity as well as flexural ductility of RC beam reinforced externally by polyurea or GFRPU. Seven specimens of four reinforced concrete (RC) beams for evaluating flexure-resisting capacity and three beams for shear-strengthening capacity are tested. The mechanical behavior and characteristics of the specimens reinforced by local and global reinforcement method classified according to strengthened area are compared. It is shown that the polyurea- or GFRPU- reinforcement leads to the enhancement in the load-resisting capacity up to 8~11% and flexural ductility within the range of 8.41~13.9 times of the non-reinforced beam. And the global reinforcement method has more improvement in the shear- and flexure-resisting capacity than the local method. It is also observed that the GFRPU can be more effectively utilized in enhancing the structural shear-resisting capacity than the flexure-carrying capacity. Doi: 10.28991/cej-2021-03091662 Full Text: PDF
Highlights
reinforced concrete (RC) members have been deteriorated by a variety of internal and external causes such as the change of design loads or the deterioration of load-resisting capacity, the increase in service periods, the change of occupation use, and the change of unexpected environment, etc
The mechanical behavior of all flexural testing specimens was similar because the tensile strength of the polyurea and Glass Fiber-Reinforced Polyurea (GFRPU) was barely improved perceptible
This study compared the enhancement in structural performance and mechanical behavior of RC beams strengthened by the GFRPU or Polyurea coating
Summary
RC members have been deteriorated by a variety of internal and external causes such as the change of design loads or the deterioration of load-resisting capacity, the increase in service periods, the change of occupation use, and the change of unexpected environment, etc. The load-carrying capacity of concrete beams should have been enhanced by strengthening techniques such as section enlargement, post-tensioning, adhesively bonded steel plates or Fiber Reinforced Polymer (FRP). Steel plates and FRP wrap laminates have been utilized as one of the common used strengthening techniques. Ghomi and El-Salakawy [2] showed improved the improved seismic performance of FRP-RC beams reinforced with steel plates. The steel plate bonding techniques have been utilized in strengthening the concrete beams owing to their economic aspect and ductile characteristics. Barnes et al [3] compared the plate attachment methods of adhesive bonding and bolting to the external surfaces of concrete beams through experiments. Thamrin and Sari [5] performed the experimental study on the flexural capacity of strengthened RC beams with web bonded steel plate. The steel plate bonding method has the principal drawbacks of its high weight and its vulnerability against corrosive environments
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