1992 Fiscal Year Final Research Report Summary
RESEARCH ON VISUALIZATION OF FRACTURE PROCESS OF SUPER-HIGH-STRENGTH CONCRETE
| Project/Area Number |
03452219
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Building structures/materials
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
TOMOSAWA Fuminori UNIV.OF TOKYO,FAC.OF ENGINEERING,PROFESSOR, 工学部, 教授 (50211404)
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| Co-Investigator(Kenkyū-buntansha) |
NOGUCHI Takafumi UNIV.OF TOKYO,FAC.OF ENGINEERING,RESEARCH ASSISTANT, 工学部, 助手 (80208321)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Super-high-strength Concrete / Fracture Process / Photographing / Bond Crack / Mortar Crack / Coarse Aggregate / Crack Arresting |
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| Research Abstract |
Mechanical properties of coarse aggregate such as compressive strength, modulus of elasticity and toughness are important for making super-high-strength concrete. In order to investigate the effect of coarse aggregate on compressive strength of super-high-strength concrete, plate specimens, in which a few types of artificial coarse aggregates were arranged in some ways, were tested in compression. When tested, the pictures of initiation and propagation of cracks under compression were taken, and the concentration and distribution of strain were measured by paper strain gauges. The test results are summarized as follows :
1.In the case that modulus of elasticity of coarse aggregates are higher than that of mortar and bond strength between coarse aggregates and mortar is very small, bond cracks occur at the early stage of loading. If the bond strength exsists in some extent, bond cracks occur at the half level of maximum stress.
2.In the case that compressive strength of coarse aggregates are higher than that of mortar, crack arresting by coarse aggregates cannot be expected if the content of coarse aggregates is small.
3.In order to make super-high-strength concrete with compressive strength of more than 120 MPa, the attention should be payd to the followings.
(1) Both coarse aggregate and mortar have compressive strength more than 120 MPa.
(2) Difference of modulus of elasticity between coarse aggregate and mortar is small.
(3) Coarse aggregate is tough.
(4) Relatively large amount of coarse aggregate exsist.
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