New Discovery of Diethyl Carbonate Modified Natural Hydraulic Lime in Heritage Conservation

Cracks are one of the common diseases on the surface and inside of stone cultural relics. The research and application of grouting materials are crucial for crack conservation of cultural relics. This work mainly studies the modification of Natural Hydraulic Lime (NHL2), a commonly used crack grouting material for stone cultural relics. Diethyl Carbonate (DEC) is used to modify Natural Hydraulic Lime to provide a carbon source within the system, and it can produce the raw material (CO2) needed for the reaction to maintain the continuous occurrence of hydration and carbonation reactions. Diethyl Carbonate-modified Natural Hydraulic Lime (DEC-NHL2) can keep the original physical phase and composition unchanged, refine the grain size, and increase the product of the hydration and carbonation reaction. In addition, it can promote the synchronous carbonation of the inner and surface parts, accelerate the coagulation rate of the slurry and improve the compressive strength, thus substantially enhancing the reaction continuity and stability of the NHL2 slurry, and avoiding the repair damage caused by stress concentration. It provides a new idea for grouting and protection of stone cultural heritages.