コンクリート用化学混和剤の遅れ添加と高流動化コンクリートに関する研究
1980 年 29 巻 318 号 p. 233-239
詳細
1980 年 29 巻 318 号 p. 233-239
Recently, much attention is being paid to new methods utilizing concrete admixtures. Perhaps it is because many kinds of concrete have been used in different fields of construction and chemical admixtures have been recognized as a necessary material in concrete.
In this study, in order to improve the properties of fresh concrete, several kinds of concrete were made in the following ways.
(1) To improve the effectiveness of water reduction, the timing of addition of admixtures was delayed for a short moment, such as 30, 45, 60 and 120 second, after mixing was finished.
(2) To recover the consistency of concrete, a water reducing admixture was added 60min. after mixing was finished.
(3) To produce a flowing concrete, a superplasticizer was added to the base concrete with a water reducing admixture 60min. later.
The measurements of slump, bleeding, setting time, entrained air content, compressive strength were carried out on these specimens.
The results, obtained showed that a high quality concrete could be achieved economically without deteriorating significantly the subsequent hydration of cement and the final products.
