抄録
To examine the effect of reduced cement content upon the properties of concrete containing admixtures, as in the air-entraining agent, five water-reducing admixtures, four water reducing-set controlling admixtures, and five brands of normal portland cement have been selected and used with some combinations.
Comparative tests have been performed of fresh concrete with respect to its water-reduction, bleeding, time of initial and final setting, and of hardened concrete with respect to its strength gain concretes with the above-mentioned admixtures with cement contents of 260, 280 and 300kg/m3, were prepared and compared with the control concrete having the cement content of 300kg/m3 and same consistency of 7.5cm without admixture.
The results of the test show that the good quality of water-reducing admixtures can reduce water requirement by 10 to 15 percent, irrespective of the cement contents, and that the strength gain, the time required for setting and bleeding are affected by reduction in cement contents, and by the quality of water-reducing admixtures.
