Abstract:The influence of slag, circulating fluidized bed combustion(CFBC) desulfurization ash and silica fume on hydrated lime were observed to explore the feasibility of modified lime in the restoration of ancient buildings and its mechanism. Results indicate that the mechanical properties, water resistance and weather durability of hydrated lime are significantly improved by slag, CFBC desulfurization ash and silica fume, due to their pozzolanic reaction and improvement of microstructure. Compared with natural hydraulic lime(NHL2), hydrated lime with slag has higher mechanical properties, water resistance, weather durability and flexibility; the performance advantage of hydrated lime with CFBC desulfurization ash is smaller; it has higher compressive strength and weather durability, weaker water resistance and flexibility while it mixed with silica fume. In the restoration of ancient buildings, 20%(by mass)slag should be used as the admixture of hydrated lime.