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Title |
Freezing and Thawing Resistance and Fundamental Properties of Antiwashout Underwater Concrete Containing Mineral Admixtures
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Keywords |
수중불분리성 콘크리트; 동결융해저항성; 고로슬래그 미분말; 간격계수; 내구성지수; antiwashout underwater concrete; freezing and thawing resistance; ground granulated blast furnace slag; spacing factor; durability factor |
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Abstract |
Today the application of antiwashout underwater concrete to the construction sites is increasing steadily, while its reliability is in issue. Particularly, antiwashout underwater concrete is known to have very weak durability on frost attack, and hence Japan society of civil engineers(JSCE) regulated that not to use of antiwashout underwater concrete where the freezing and thawing is suspected. This study aims the improvement of the freezing and thawing resistance for antiwashout underwater concrete. From the results of fundamental test, FA20 and SG50 showed good performance in fluidity and long term compressive strength than control concrete. Meanwhile, MK10 marked the highest compressive strength through the whole curing age but a defect on fluidity was discovered. The results from the repeated freezing and thawing test show that the large volumes of air entrapped by cellulose based antiwashout underwater admixture gave bad effects to frost durability and hence not much benefits were confirmed from the use of mineral admixtures. However there were some increasing effects on frost durability of MK10 and SG50 by securing 6±0.5% of entraining air. In the meantime, there was a increasing tendency of frost durability by increasing blame's fineness of ground granulated blast furnace slag.
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