2007 Fiscal Year Final Research Report Summary
Utilization of fiber reinforced concrete to control crack width of reinforced concrete structures
| Project/Area Number |
18560450
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Civil engineering materials/Construction/Construction management
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| Research Institution | Gifu University |
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Principal Investigator |
UCHIDA Yuichi Gifu University, Information and multimedia centen, Professor (20213449)
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| Project Period (FY) |
2006 – 2007
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| Keywords | concrete / fiber reinforced concrete / crack / bond / finite element analysis |
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| Research Abstract |
1. Crack behavior of reinforced concrete beams using various types of fiber reinforced concrete (ordinarily steel fiber reinforced concrete and two types of high performance fiber reinforced cement composites with multiple fine cracks (HPFRCC)) was investigated through the flexural loading tests. The crack width was decreased by using the fiber reinforced concrete in the tensile region of the beam. The crack width of the beams using HPFRCC was little than 0.1mm even at yield loading level. However, the crack distribution of the beams was influenced by material properties of HPFRCC.
2. The tensile tests of uniaxial reinforded concrete specimens were carried out to clarify the influence of fiber reinforced concrete on the crack width and bond property between the concrete and the steel bar. There were little differences between bond property of the plain concrete and that of the fiber reinforced concrete.
The reducing effect of crack width by using fiber reinforced concrete was caused by the bridging effect of the fiber at the crack surface. The bridging effect of the fiber was evaluated by the tension softening curve of the fiber reinforced concrete.
3. The finite element analysis on the uniaxial reinforced concrete specimen and the pull out specimen were carried out to clarify the mechanism of the bond behavior. The combination of the very fine mesh model and the compression softening model for the concrete material property caused the compressive strain localization at the front of the rib surface of the deformed steel bar. The bond slip at the high stress level could not be simulated due to the strain localization. The macroscopic bond model was proposed to overcome the problem of the strain localization. The bond slip was represented by the shear deformation of the bond damaged layer around the steel bar in the proposed model.
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