Quantification of residual cement paste on recycled concrete aggregates containing limestone by selective dissolution

This study proposes a new method of selective dissolution of calcium from C-S-H and CH phases by deionized water to evaluate the cement paste content in recycled concrete aggregates (RCA). The selective dissolution tests were carried out in standard phases of hydrated cement paste (HCP), calcite, dolomite and quartzite sand, and mixtures simulating RCA containing 1,5,10,20% HCP. The materials were characterized by X-ray diffractometry, thermal analysis, Raman and infrared spectroscopic analyzes, chemical analysis and laser diffraction analysis. Materials characterization indicates good selectivity of the deionized water in the calcium dissolution of the CH and C-S-H compared to limestone. (C) 2019 Elsevier Ltd. All rights reserved.