1999 Fiscal Year Final Research Report Summary
Investigation on Frost Deterioration of Concrete Using Limestone Coarse Aggregate
| Project/Area Number |
10650552
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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 |
Building structures/materials
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
SENBU Osamu Hokkaido Univ., Grad. School of Eng., Assoc. Pro., 工学研究科, 助教授 (10236127)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Limestone / Coarse Aggregate / Concrete / Frost Deterioration / Thermal Coefficient / Stone Powder |
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| Research Abstract |
Although limestone is characterized by low water absorption and high specific gravity, it is said that frost durability of concrete with the limestone coarse aggregate is lower than concrete with the good coarse aggregates. In this paper, frost durability of concrete with the limestone aggregate is investigated. Results are shown as follows:
(1) According to the investigation of the past experiments, frost durability of concrete was not explained satisfactory by the basic property of coarse aggreegate.
(2) According to the test results of the basic property test of the limestone coarse aggregate, the limestone is characterized by low water absorption, high specific gravity, low thermal coefficient and high content of stone power.
(3) Differences of the thermal coefficient between the coarse aggregate and mortar cause thermal stress, and the low thermal coefficients of limestone cause large thermal stress. It is thought that the thermal stress affects frost deterioration of concrete.
(4) For concrete, an existence of stone powder has effects of reducing air content and improving frost durability.
(5) Freezing and thawing tests varied volume and the surface area of the coarse aggregate was conducted. It is thought that the effect of the thermal stress magnitude on frost durabllity of concrete is small. When the number of the coarse aggregate becomes large, frost durability of concrete becomes small. It is thought that number of cracks affect frost durability of concrete becomes small. It is thought that number of cracks affect frost durability of concrete.
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