Rheological behavior and compressive strength of concrete made with recycled fine aggregate of different size range

This study aims to examine the rheological properties and compressive strength of concrete containing recycled fine aggregate (RFA) with different particle size ranges. A developed polycarboxylate superplasticizer (SP2) was firstly applied in this study to optimize the rheological properties of concrete with RFA. The evolution of rheological properties of concrete containing RFA with the similar initial slump were investigated. Experimental results showed that the developed SP2 was more compatibility with RFA than ordinary polycarboxylate superplasticizer because of the lower static and dynamic yield stress when the slump was in the similar range and the lower time loss of slump in the range of 5.00%-11.63% in 30 min. The finer particles of RFA, smaller than 0.15 mm, led to the slow evolution of static yield stress and higher plastic viscosity in 30 min. Rheological properties of corresponding mortar were closely related with concrete. Different particles size range of RFA had clear impact on the compressive strength of concrete. The RFA with finer particles, smaller than 0.15 mm, had relative lower strength. But RAC-3 had the highest compressive strength, which may be attributed to the continuous gradation and denser packing structure of RFA in the particle size of G3.