유지류를 중심으로 한 수축저감제 종류 변화가 고강도 콘크리트의 기초물성 및 자기수축에 미치는 영향

Abstract

In this research, the fundamental properties and autogenous shrinkage behaviors of high strength concrete of 0.30 water-to-binder ratio was evaluated depending on the various shrinkage compensating admixtures such as soybean oil (BO), wasted cooking oil (WO), and emulsified refined cooking oil (ERCO) comparing to commercial shrinkage reducing admixture (SR), and expanding admixture (EA). According to the experiment results, the workability of the concrete mixture showed decreased when it contained BO, and WO rather than Plain. In the case of ERCO, due to the water dispersing effect caused by emulsification, similar workability was obtained to Plain. For compressive strength, the concrete mixtures with BO, and WO decreased compressive strength rather than Plain concrete mixture, while the concrete mixture with ERCO showed decreased compressive strength at early age and recovered strength at later age. Regarding the autogenous shrinakge reducing performance, the oil-based admixtures of BO, WO, and ERCO showed better performance than SR and EA; it is considered that the saponification, the hydrolyzed reaction of fatty-acid from oils by calcium hydroxide, the hydration product of cement paste, contributes on filling the capillary pores of the concrete matrix, and thus it decreases the shrinkage. eventually, workability, strength, autogenous shrinkage reducing of 30~40 %, and economical aspects, it can be state that using ERCO may be an efficient solution for autogenous shrinkage of high strength concrete.