Research on the long-term effectiveness of preservation materials of ancient mortar
High hydrophobic preservation materials can cause damage to the ancient chinese construction material known as tabia.
Tabia was a very popular construction material
-Tabia was a very popular construction material with high mechanical strength, great tenacity and good impermeability, which was widely used in ancient China. Organic additives, such as sticky rice, egg white and sugar are believed to be added to some tabia.
Silicone has commonly been used to preserve and protect tabia relics. However, it was recently observed in numerous circumstances, that the addition of silicone facilitates failures on the consolidated parts, e.g., warping and detachment, thereby accelerating the destruction of the tabia relics.
Thus, the goal of a new study is to perform preliminary research work on the long-term effectiveness of tabia preservation materials. Two silicone tabia preservation materials with different hydrophobicity were prepared. Tetraethoxysilane (TEOS) supplemented with additives hydroxyl-terminated polydimethylsiloxane (PDMS-OH) and cetyltrimethylammonium bromide (CTAB) with a static water contact angle of 110°, served as the low hydrophobicity preservation material; while hexadecyltrimethoxysilane (HDTMS) with a static water contact angle of 110° provided the high hydrophobicity preservation material.
High hydrophobicity of preservation material facilitates damage
Both the two preservation materials were used on the Zhenyuan Tabia Fort in Ningbo City, Zhejiang Province, China. Multi-factor deterioration experiments, including capillary water absorption with Na2SO4 solution, salt crystallisation, freeze-thaw cycle, and wet-dry cycle were performed to assess the causes of the damage induced by the preservation materials. The results indicate that the use of the high hydrophobicity of preservation material facilitates damage to the tabia relics.
The study has been published in Progress in Organic Coatings, Volume 145.
Image source: Pixabay.
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