Title:
Effect of Synergistic Activation on the Properties of Recycled Concrete Powder (Prepublished)
Author(s):
Shuiping Li, Chengxiao Yu, Jincheng Jiang, Bin Yuan, Jian Cheng, and Qing Lin
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
microstructure; cement paste; recycled concrete powder; strength development; synergistic activation
DOI:
10.14359/51749295
Date:
10/30/2025
Abstract:
The amount of recycled concrete powder (RCP) experiences an exponential increase due to the construction and demolition activities associated with buildings and infrastructure. To enhance the reactivity and utilization of RCP, this study investigated the effect of thermal (calcination), inorganic (calcium hydroxide, CH), organic (diethanolisopropanolamine, DEIPA), and synergistic activation on the strength development of recycled concrete powder-cement (RCP-C) pastes. The microstructure of hardened pastes was characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric (TG) analysis, and scanning electron microscope (SEM). The results indicated that the optimal compressive and flexural strength were achieved when pastes were activated by calcination at 700°C for 30 minutes, followed by inorganic and organic activation using CH and DEIPA as activators successively. The compressive (flexural) strength at 1, 3, and 28 days increased by 42% (26.9%), 27.0% (18.6%), and 25.5% (16.3%), respectively, compared to the control group. The microstructure analysis revealed that the enhancement mechanism can be attributed to a thermal-inorganic-organic synergistic activation.