Mechanism and effect of alkoxysilanes on the restoration of decayed wood used in historic buildings

It was necessary to protect and restore the decayed wood in the ancient buildings, in which reinforcing and restoring the damaged components with in situ and non-destructed strategy was preferred, following the heritage protection principles. For this purposes, series experiments were designed and performed to investigate the reaction mechanism and effects of ethyl orthosilicate and methyl triethoxysilane toward the decayed wood components sampled from Shuiyu Village, a historical tribe in Beijing. The results demonstrated that the organosilicon layer was fabricated onto the wood cell walls by condensation reaction, in which the Si-O-Si bonds were formed between alkoxy groups, and the Si-O-C bonds were generated between cellulosic fibers and organosilicon. The organosilicon layer contributed to further improve physico-mechanical performances like hydrophobicity, mechanical properties, thermal stability of treated wooden components, except a slight color deviation. In all, the matrix of the ethyl orthosilicate and methyl triethoxysilane is a reliable agent for retaining the decayed part of wood components, which accomplished the satisfied performance improvements. (C) 2019 Elsevier Masson SAS. All rights reserved.