2000 Fiscal Year Final Research Report Summary
Practical Application of Structural Super Lightweight Aggregate Concrete
| Project/Area Number |
11555116
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
土木材料・力学一般
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
NIWA Junichiro Tokyo Institute of Technology, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (60164638)
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| Co-Investigator(Kenkyū-buntansha) |
HAMADA Yuzuru DPS Concrete, Technical Research Center, Chief Manager, 技術センター, 主任研究員
OKAMOTO Takahisa Taiheiyo Cement, Central Research Laboratory, Executive Director, 中央研究所・第二研究部, 部長(研究職)
OTSUKI Nobuaki Tokyo Institute of Technology, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (40211106)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Super Lightweight Aggregate / Prestressed Concrete / Fracture Mechanics / Fracture Energy / Shear Resisting Capacity / Size Effect / Composite Structures / Tension Softening Curve |
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| Research Abstract |
Recently, super lightweight artificial aggregates have been developed in Japan. The specific gravity is around 0.8 to 1.2, and the absorption ratio is less than 3.0%. The compressive strength is more than double of conventional artificial aggregates. In this research, the practical application of this structural super lightweight concrete (SLC) has been investigated.
As the first step of this research work, fracture properties of SLC, and shear resisting capacities of reinforced and prestressed SLC beams have been investigated based on the experiments. As the result of this study, the following findings have been obtained. (1) The fracture energy of SLC is much lower than normal aggregate concrete having the same compressive strength level. The shear capacity of SLC beams also shows the same tendency. (2) The increase in the compressive strength of SLC does not provide the significant increase in the fracture energy. (3) To improve the shear resisting capacity, the mix of short fiber, s
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uch as polyvinyl alcohol short fiber, is very effective in the material viewpoint. The use of prestressing is also very effective to improve the shear capacity of SLC beams.
As the second step, two countermeasures have been tried to improve the shear capacity of SLC beams. The first one is the intentional decrease in the compressive strength of SLC beams, and another one is the mixed use of super lightweight aggregates with normal aggregates, such as crushed stone. After the research work, it is confirmed that these two methods are quite effective regardless of the specific gravity of super lightweight aggregates. Finally, for the practical application of SLC, the trial design of SLC composite girders has been carried out. The aesthetic evaluation by using the computer graphics is also performed. From the trial design, SLC composite girders can reduce the dead weight of super structures to almost 50% of the conventional PC girders. SLC can provide the slender and smart concrete structures. Less
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