SiO2/TiO2 Nanoparticles within a Silica Material for the Consolidation of Sandstone Cultural Relics

Abstract To address the problems of weathering deterioration of outdoor sandstone cultural relics due to water erosion, salt weathering, and mechanical property degradation, and to extend relic preservation longevity, this study investigated the application of SiO2/TiO2 nanoparticle-modified ethyl silicate (KSE300) in the anti-weathering consolidant for sandstone cultural relics. The study used SiO2/TiO2 nanoparticles as the core modification component and combined them with KSE300 to prepare a anti-weathering composite material. The material was applied onto the sandstone surface via a single-sided brushing method for sandstone consolidation. The experimental results showed that for sandstone treated with composite particles modified KSE300, the color difference remained within the acceptable range for cultural relic consolidation and the original relic appearance was not altered. When the composite particle content was 0.15 wt %, the mechanical properties of the consolidated sandstone were significantly improved, with the compressive strength increasing from 48.23 MPa to 70.55 MPa and the hardness increasing from 573.38 HL to 579.71 HL. The sample also showed excellent hydrophobic properties, with a contact angle of 125.5°. After 14 cycles of sodium sulfate aging tests, sandstone treated with the modified material at this concentration still exhibited good salt resistance and effectively resisted outdoor salt weathering damage. This study confirmed the feasibility and superiority of the modified material, providing a reference for the research and application of anti-weathering consolidants for sandstone cultural relics.