A Study of Properties of Creep in Concrete at Early Ages
| Project/Area Number |
04650422
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
コンクリート工学・土木材料・施工
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
UMEHARA Hidetaka Nagoya Institute of Technology, Civil engineering, Associate Professor, 工学部, 助教授 (70151933)
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| Co-Investigator(Kenkyū-buntansha) |
UEHARA Takumi Nagoya Institute of Technology, Civil engineering, Lecturer, 工学部, 講師 (60231172)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1992: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Creep / Thermal Stress / Mass Concrete / Early Ages / Compensation Plane Method |
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| Research Abstract |
Creep in concrete at early ages seems to be one of the most important physical properties affected to thermal stress. But, there are few data of creep strain measured in concrete at early ages.
In this study creep tests of concrete at early ages are conducted using two kinds of equipments ; one for compressive creep and the other for tensile creep. The lever system is used for these equipments, and temperature and humidity of a concrete specimen can be controled. The rate of stress, period of loading and temperature are selected for parameters of creep tests.
The equation to calculate creep strain is derived from the testing results using viscoelastic rheology model, and adopted to the analytical method for calculating thermal stress. Furthermore, the thermal stress analysis considering creep effect is applied to the reinforced concrete box culvert in which thermal stresses are measured, and creep model is examined with comparing analytical results of thermal stress to measured results.
The results gained in this study are summarized as the followings ;
1. It is clear that the higher the temperature rises, compressive creep as well as tensile creep become larger and the shorter the period of compressive loading and the higher the compressive stress at that time are, the tensile creep strain become larger.
2. It is clear that as the structural formula for creep of concrete at early ages the 4-element model conforms the best with the test results on the compression side and the 5 element model does the same on the tension side.
3. As the result of the thermal stress analysis made on the box culvert using the effective modulus of elasticity obtained from the structural formula for creep, the values gained by the analysis conform with those actually measured. From these facts, good prospect is gained for estimation of the thermal stress by applying the creep model constructed in this study.
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Report
(3 results)
Research Products
(9 results)
