Consolidation and surface protection of granite using modified polysiloxane oligomers for cultural heritage restoration

Consolidation of severely weathered stone cultural relics and surface protection for the conservation and restoration of stone materials are currently crucial and challenging tasks in cultural heritage conservation. A variety of reinforcing and sealing materials exist, attributed to the diverse geographical locations and climatic environments of relics. In this study, the influences of materials on pore structure, hardness, color difference, and gloss changes were evaluated by investigating granite treated with modified polysiloxane oligomers through microscopic observation, permeability tests, artificial aging tests, breathability tests, and water absorption tests. Results showed that the 30% polysiloxane-D40 solution (Sample A) achieved the highest penetration depth (12.3 mm), while the 15% solution (Sample D) provided the best hydrophobicity (water absorption rate: 0.38%) and minimal color change (ΔE = 2.7). The combined use of A and D significantly enhanced both structural and surface properties. The combined application effectively protects granite relics, laying a significant foundation for future conservation and restoration of granite cultural relics in Fujian Province.