Abstract：Using recycled micropowder (RCP) as cement-based cementing material can effectively utilize construction waste. However, cement mortars containing RCP usually exhibit poor performance due to the low activity and high porosity of RCP. In order to solve this problem, ammonium chloride was used to improve RCP, which replaced 10% cement to prepare mortar. The effects of RCP substitution level modified by ammonium chloride on hydration properties, mechanical strength and pore structure of cement mortar was investigated. The experimental results show that the particle size of RCP soaked in ammonium chloride solution is smaller, which is conducive to the hydration of cement. Ammonium chloride reacts with calcium-based components such as C-S-H to generate active silica gel, which optimizes the pore structure of RCP mortar, thereby enhancing the compressive strength of RCP mortar. The compressive strength of RCP mortar of the optimal group is about 15.5% higher than that of untreated RCP mortar, which is close to that of pure cement mortar
2025, Vol. 0 
