Effect of plasticizer dosage on properties of multiple recycled aggregate concrete

Abstract

Recently, studies on multiple recycling of concrete have been attracting attention. In general, multiple recycling increases adhered mortar content of aggregate, consequently, the water absorption of the multiple recycled aggregate is increased, and the slump of concrete with the multiple recycled aggregate is reduced. Therefore, this study attempted to offset the slump loss by increasing the plasticizer dosage, and investigated the effect of the increased plasticizer dosage on the various properties of multiple recycled aggregate concrete. The properties investigated included slump, air content, density, compressive strength, splitting tensile strength, ultrasonic pulse velocity, and capillary absorption. The results showed that all selected properties of the multiple recycled aggregate concrete were lower than those of reference concrete at the same plasticizer dosage due to the lower quality of the multiple recycled aggregate. However, the slump could be improved by adjusting the amount of plasticizer, and furthermore, within a certain range, the increase of the plasticizer dosage improved the density, sorptivity, and mechanical strength, demonstrating the multiple recycled aggregate concrete could achieve requirements for the use of structural concrete. © 2023, Springer Nature Japan KK, part of Springer Nature.