Influence of Superretarding Admixtures on the Properties of Cement and Concrete.

超缓凝外加剂对水泥和混凝土性能的影响。

基本信息

批准号：
61550420
负责人：
SHIIBA Hiroyuki
金额：
$ 1.28万
依托单位：
Fukuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

In these days, it has become necessary to ensure a monolithic structure of concrete. Therefore the avoidance of cold joints is essential and superretarding admixtures prolong the setting time for which concrete can be vibrated.A conciderable amount of research has been carried out to elucidate the mechanism by which superretarding admixtures delay the setting time of cement concrete. It has been suggested that adsorption of organic compounds on the surface of the cement compounds prevent reaction with water.However, it has been shown that superretarding admixtures are not strongly adsorbed on the cement hydration products. Because the adsorption by the C_3S (which contributes to the concrete's early strength) is low, it is considered that an adsorption mechanism is not the primary cause of retardation.This paper describes the results of fundamental studies on the physical effects of superretarder added cement and concrete. Therefore the extent of the knowledge has been obtained for early compressive strength, young's modulus and workability according to setting time by penetraction resistance methods, and for the construction joints of concrete in which splitting tensile strengths and flexural strengths of horizontal and vertical construction joints between new and old concrete under the various conditions.

如今，有必要确保混凝土的整体结构。因此，避免冷缝是至关重要的，超缓凝外加剂可以延长混凝土振动的凝结时间。为了阐明超缓凝外加剂延迟水泥混凝土凝结时间的机理，已经进行了大量的研究。有人认为，水泥化合物表面上有机化合物的吸附可防止与水发生反应。然而，研究表明，超缓凝外加剂在水泥水化产物上的吸附并不强烈。由于C_3S（有助于混凝土的早期强度）的吸附性较低，因此认为吸附机制不是缓凝的主要原因。本文介绍了关于添加超缓凝剂的水泥和物理效应的基础研究结果具体的。因此，我们已经获得了通过渗透阻力法根据凝结时间确定的早期抗压强度、杨氏模量和和易性的知识范围，以及对于混凝土施工缝（其中新混凝土施工缝之间的水平和垂直施工缝的劈裂拉伸强度和弯曲强度）的了解程度。以及各种条件下的旧混凝土。