Systematic evaluation of the effect of replacing river sand by different particle size ranges of fine recycled concrete aggregates (FRCA) in cement mortars

摘要

This study explored an alternative way to reuse fine recycled concrete aggregate (FRCA) in cement mortars by using a new designed method to replace natural aggregates. The river sand (RS) in different particle size ranges with varied lower limits (i.e., 4.75-236 mm, 4.75-1.18 mm, 4.75-0.6 mm, 4.75-0.3 mm and 4.75-0.075 mm) were replaced gradually by the corresponding FRCA. As a comparison, same particle size ranges of fine crushed stone (FCS) were also used as replacement of RS. All types of mortars were controlled by a similar consistency. The results showed that the decrease in the lower limit of the replaced particle size range of FRCA (R-L(FRCA)) tended to cause reductions in the compressive and flexural strength and increases in the drying shrinkage of the mortars. Using different particle size ranges of FRCA to replace RS in mortars resulted in more adverse effects on the strength and drying shrinkage than incorporating the corresponding FCS. The results of this study could provide a guidance on which particle size ranges of FRCA could be used as the replacement of RS in cement mortars for specific performance requirement. (C) 2019 Elsevier Ltd. All rights reserved.