Effects of Placement Interval of High-Fluidity Concretes

Abstract

High fluidity concrete has been used to meet requirements for marine construction thanks to its superior durability and ease of placing. High-fluidity concrete, however, having high viscosity and less bleeding, may form cold joints that may harm the uniformity of the structure. We have conducted a series of experiments to study the effect of interval and method of making joints on the strength of placing-joint of three types of high-strength and high-fluidity concrete and two types of high-fluidity lightweight concrete for marine construction. The strength of the placing-joint has shown no substantial degradation compared to those without placing-joint by rodding the joint within 120 minutes after the first placing under an ambient temperature of 20 deg C, while specimens without rodding, cured under the standard water bath, have shown 2/3 of the strength of those without placing-joint at an interval of placement less than 60 minutes.