| 요약2 |
This study is to investigate the development of high early strength agent, considering both early strength development and economic effect, in order to improve early strength development of concrete incorporating mineral admixtures being recently used. Importantly, powder type agents caused several problems, when added in concrete and considered the economic influence, so that this study designed diverse admixture types as experimental factors. A specimen adding standard type of AE water reducing agent is set as a control mixture and other specimens add various admixtures, such as MAS type of liquid type high early strength agent, polycarboxylic type and naphthalene+lignin type of ordinary water reducing agent, respectively. The standard type of AE water reducing agent was added in specimens for only one level, which can satisfies target fluidity and air content, while MAS type of liquid type high early strength agent was added in specimens for three levels, 0.5, 1.0 and 1.5%, and ordinary water reducing agent was two level, which is same content as control concrete. According to those different content of admixtures, the fundamental properties of each specimen is examined. As results of the test, the MAS type of liquid type high early strength agent decreased fluidity, increased air content and accelerated setting time. In addition, the MAS type agent improved the early strength, compared with normal used type of early strength AE water reducing agent. Specimens adding the MAS type agent resulted in the increase of air content of fresh concrete for about 2%. This result demonstrated that if the air content revised to the value of control concrete, it would be expected that the strength improvement of specimens adding MAS type agent will be more increased. |