Mix Design Method for Self-Compacting Recycled Aggregate Concrete and Its Microstructural Investigation by Considering Adhered Mortar in Aggregate

Abstract

This article is on the development of a mix design method for self-compacting recycled aggregate concrete (SCRAC) by considering the adhered mortar content (AMC) on the surface of the aggregate. In this method of mix design, the acceptable percentage of recycled concrete aggregate (RCA) depends on the AMC value. Five different batches of design mixes were prepared, including one batch that used conventional design from natural aggregate, two batches that used conventional design from RCA, and two batches that used the proposed design from RCA. In one batch from each of the conventional and proposed design mixes, the RCA was treated with a sodium silicate solution and silica fume in order to assess the effect of treatment. In addition, each of the batches consisted of three different sub-batches prepared with different mixing approaches. The microstructural analysis revealed the reason for best mechanical properties prepared with treated RCA along with proposed two-stage mixing approach (TSMA).