STUDY ON THE FLUIDITY, PLACEMENT ABILITY AND PROPERTIES OF HIGH-FLUIDITY CONCRETE

摘要

J shaped flow test has been developed in order to evaluate the fluidity of high-fluidity concrete measuring the shearing yield value and the viscosity. This paper is intended to study the effects of mix proportions on the fluidity or rheological parameters of the high-fluidity concrete by using the J shaped flow test and the effects of rheologicla parameters on the placementability of the fresh concrete and the properties of hardened concrete such as compressive strength and dry shrinkage. The main results are as follows; 1)Visosity of high-fluidity concrete are found to be mainly dependent on the quantity of superplasticizer,the quantity of segregation reducing agent and water cement ratio. 2)Shearing yield value of high-fluidity concrete are found to become low as quadratic function of quantities of superplasticizer. 3) Placement ability of high-fluidity concrete is found to be satisfactory when shearing yield value is less than about 40Pa.4)When viscosity of high-fluidity concrete is less than 50 Pa.s,quality of high-fluidity concrete is seemed bo be unstable.