Characteristics of Excess Water Dewatered Concrete Using Permeable Liner

In this study, to enhance the quality of concrete surface by removing the surplus water, permeable liner attached the euroform was applied for manufacturing concrete specimens. Various kinds of concrete mixtures with different water to binder ratios were applied and the strength properties of the hardened concrete surfaces were evaluated at different heights. Experimental results showed that the rebound values by schmidt hammer test and the compressive strengths on the surfaces of concrete specimens were increased as proportion to the amount of mixture water which is dependent on the water to binder ratio of each concrete mixture, and more enhancements were observed on the middle and lower specimen surfaces than the upper region. SEM analysis also showed that much denser hydrate structures were observed on the specimen surfaces by the application of the permeable liner while similar hydrate formations were occurred regardless of surface treatment conditions. From the MIP test results of the concrete surfaces, it was observed that, by the application of permeable liner, the pore volume below $0.01{\mu}m$ was decreased with a maximum of 50% resulting in the densification of pore structures.

투수시트를 적용하여 잉여수를 탈수한 콘크리트의 강도 특성

이 연구에서는 콘크리트 타설 시 발생하는 잉여수를 제거하여 피복 콘크리트의 성능을 향상 시키고자 거푸집에 구멍을 뚫지 않은 일반 유로폼에 투수시트를 부착하여 타설한 콘크리트의 물-결합재비 종류 및 시험체 높이에 따른 강도 특성을 분석하였다. 슈미트해머 반발경도 및 압축강도의 경우 투수시트면이 물-결합재비가 높은 배합일수록 크게 나타났으며, 시험체의 높이에 따라서는 상부보다는 중부 및 하부에서 크게 나타남을 알 수 있었다. SEM 분석 결과의 경우 수화물의 생성형태는 유사하였으나 투수시트면이 일반면에 비해 공극이 확연히 감소되고 밀실해 지는 것으로 나타났으며, MIP 분석 결과 투수시트를 사용하였을 경우 $0.01{\mu}m$ 이하 공극량이 최대 50%까지 감소되어 공극이 치밀해지는 것으로 나타났다.