Study on applying inorganic polymers to restore rammed earth brick monuments

Rammed earth has been used as a building material in China for thousands of years. However, due to weather and environmental impacts, monuments built from rammed earth suffer from varying degrees of damage. To restore these structures effectively, the authors heated kaolinite featuring the same characteristics of rammed earth and added glass powder and sodium hydroxide to make inorganic polymers. Subsequently, using various mix ratios, calcination temperatures and calcination times, the compressive strength of the clay produced was investigated. It was determined that by controlling the inorganic polymers and clay ratio at 1:1 and calcinating the mixture at 300°C for 1 h, the compressive strength could be increased to 430·9 kg-force/cm². This result met the Chinese national standards for red bricks, and the proposed material consumed only 1% of the energy used during the red brick burning process. The proposed method substantially reduced carbon dioxide (CO₂) emissions while conserving energy. These results verify that inorganic polymers can be applied to rammed earth used to restore monuments.