Study on the In-Laboratory Screening of Sandstone Grotto Patching Materials Based on Hydraulic Lime

This study explored the effect of compounding artificial hydraulic lime and silica fume for use as a sandstone grotto patching material. Different proportions of silica fume were added to hydraulic lime in lab tests, and their effects on the mortar's physical and mechanical properties were studied. The results show that adding silica fume significantly increased the flexural and compressive strengths of the mortar and the shrinkage rate. A comparative analysis revealed that the comprehensive performance of the mortar reached the optimal state when the silica fume content was 10%. This met the strength requirements of repair materials for sandstone grottoes, as well as the control requirements regarding the shrinkage rate. Additionally, it demonstrated excellent weather resistance. This study's results provide a scientific basis for the restoration of sandstone grottoes and the screening of an appropriate ratio of repair materials, which holds significant practical application value for the protection and reinforcement of stone relics.