The Influence of Admixtures on the Technological Properties of Fresh Concrete Mixture

摘要

In this research superplasticizing (SP), air voids removing (AVR), viscosity modifying (VM) and air entraining admixtures (AE) were used. The dosage of admixtures was chosen from minimum to maximum values recommended by the manufacturers. To sum up, 7 concrete mixture compositions with SP, 6 with AVR and 6 with VM and the last 6 with AE admixture were prepared. Water and cement ratio for all the compositions was kept at the same value. According to the results obtained, the usage of SP admixture resulted in significant increase of mixture`s slump and flow however it reduced mixture`s air content and increased its density. Concrete mixture`s properties: slump and flow were almost not affected by the increase of AVR and VM admixtures, however the air content slightly decreased and the density of concrete mixture slightly increased. With the incline of air entraining admixture, mixture`s slump, flow and air content increased, but the density declined. The authors of this study wanted to express the importance of the close link between concrete mixture`s technological and rheological properties. According to the yield stress of concrete mixture it is possible to prognosticate the future problems or various outcomes during or after the concrete mixture`s casting process.