| Project/Area Number |
61460178
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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 | Kyushu University |
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Principal Investigator |
MATSUFUJI Yasunori Kyusyu University . Professor, 工学部, 教授 (20037922)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAKAMI Yoshihito Toway University . Lecturer, 工学部, 講師 (60128006)
NAKATAKE Mikio Kyusyu University . Assistant, 工学部, 教務員 (30101174)
OHKUBO Takaaki Kyusyu University . Assistant, 工学部, 助手 (60185220)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 1987: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1986: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | Ultrasonic Shear Wave / Concrete / Controll of Exection Schedule / 凝結試験 / 非破壊試験 / 凝結過程 / 動的ずり弾性率 / 動的ずり粘性率 |
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| Research Abstract |
In this study, we investigated the properties of concrete by means of travelling ultrasonic pulsed shear wave. The results are summarized as follows.
1. Application for testing method for time of setting
The setting time is defined by the characteristics of the dynamic shear modulus-elapsed time curve. It becumes clear that the setting time, varied with water-cement ratio of the mixture, temperature, admixture, and so on, has a significant meaning for exection schedule of concrete work.
2. The characteristics of the ultrasonic shear wave travelled through concrete
The power spectrum of the response function of concrete in the early age is limited in the lower frequency range, and the peak frequency dose not agree with that of the operated frequency. It is found that the phenomena is caused by the characteristics of attenuation coefficient of concrete. That is the curves of attenuation coefficient versus frequency have a minimum at each age, and the point shifts to higher frequency with age.
3. Application for non-destructive testing methods of concrete
It is found that the compressive strengh of concrete is estimated accurately by it's dynamic shear modulus of cement paste which is calculated by applicating the theory of elasticity of two phase systems The advantage of this method is that compressive strength of concrete is determined independently of mix or age.
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