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

在这些日子里，有必要确保混凝土的整体结构。因此，避免冷缝的产生是十分必要的，而超缓凝外加剂可以延长混凝土的振捣凝结时间。有人认为，有机化合物在水泥混合物表面的吸附阻止了与水的反应，然而，已经表明，超缓凝外加剂在水泥水化产物上的吸附并不强烈。由于对混凝土早期强度有贡献的C_3S的吸附作用很小，因此认为吸附机理不是缓凝的主要原因。因此，通过抗拉方法，获得了早期抗压强度、杨氏模量和工作性（根据凝结时间）以及混凝土施工缝的知识程度，其中新老混凝土之间的水平和垂直施工缝在各种条件下的劈拉强度和弯曲强度。

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.