<p>The physical and mechanical properties of grouting material are critical indicators to assess its compatibility to earthen sites as a fissure repair material. This study activated the clay from Huangshan Archaeological Site by calcination to explore how calcined clay enhances the age performance of grouting material with various temperature and blending ratio. The results revealed calcined clay’s effect of improving water retention and density of the slurry, reducing shrinkage and colour difference. The mechanical strength increased first and then decreased with rising calcination temperature, as clay’s mineral activity was altered by phase transformation. At the microstructural level, stable minerals such as quartz and calcite provided a framework, while hydration products such as calcium silicate hydrate (CSH) and tetracalcium aluminate hydrate (C₄AH₁₃) interwove to form a denser pore structure. This modified grouting material with calcined clay demonstrates feasibility for earthen site restoration.</p>