| 요약2 |
The purpose of this study is to put to practical use high-strength concrete in which over-added crushed sand is used. An indoor mixing test as to crushed sand substitution rates 0∼100% was implemented, and based on its results, the productivity evaluation of the batcher plant followed. First, the compressive strength of the indoor mixing test showed somewhat different results according to the water-binder ratio. That is, when the water-binder ratio was 0.25, the compressive strength in the 28th increased slightly as the crushed sand mixing ratio was getting higher. However, when the water-binder ratio was 0.30 and 0.35, the crushed sand mixing ratio increased up to 50%; but it was found to decrease gradually in the higher crushed sand mixing ratio than that(0.30, 0.35). As to the modulus of elasticity, the result of this study was estimated to be 9.57% lower than that of the current concrete standard specification. As to the heat of hydration in the batcher plant mixing test, the highest temperature decreased by about 11℃ and the highest temperature rose by about 9℃ as the water-binder ratio increased by 0.1. The compressive strength of the specimen for the structure management was 7% higher than the standard cure specimen in the case of the on-site sealing cure, and 2.7% in the case of the on-site underwater cure. In conclusion, as a result of mixing at the rate of 1(50%) to 1(50%)crushed sand, which had somewhat improper quality to be used as concrete aggregate with 3.98 of fineness modulus and 52.7% of solid volume percentage for shape determination; and sea sand, which had relatively excellent quality and the fineness modulus of 2.8(the fineness modulus : 3.23), it was proven that there was no significant problem in manufacturing high strength concrete with the specified compressive strength around 40∼70MPa. |