(CS1.2) Performance Evaluation of Chemical Poultice Removal of Silane & Siloxane Water-based Water-Repellent Treatments on Hand-Molded Bricks

This research endeavors to assess the efficacy of chemical methods in removing water-repellent coatings from hand-made brick substrates. This investigation is imperative given the widespread inappropriate application of hydrophobic materials over the past five decades, necessitating their removal due to resultant damage to the brick substrates. Additionally, there is a growing need to ascertain if penetrating water repellent treatments are retreatable and compatible, particularly for their continued use in preservation treatments for historical buildings.

The research employs solvent-based and alkaline-based chemical removal techniques, combined with poultice application, to eliminate silane & siloxane water-based water repellent treatments from brick surfaces. Through analysis encompassing physical examination (microscope observation and ultraviolet-light observation), hydrophobicity assessment (water vapor transmission test by ASTM and water absorption RILEM test) and chemical analysis by using reflectance (FT-) IR spectroscopy, the primary objective is to assess the effectiveness of various chemical products and also the harmful effects on the brick substrate. This research is still in process and will be finished by May, 2024. The data and conclusions are in discussion.