A plaster with kaolin residue as an alternative to the Amazonian reality in the safeguarding of cultural assets

Abstract

The conservation of cultural heritage needs to be aligned with current sustainability policies. Therefore, this work aimed to assess the effectiveness of using kaolin residue, either totally or partially replacing bentonite, in Mário Mendonça de Oliveira's formulation for cleaning stone surfaces, in order to measure possible changes in the appearance or structure of Lioz stone. The influence of some variables, such as the application time of the plaster and the concentration of the clay minerals used, was evaluated. The experimental methodology consisted of drying and pulverizing the residue; quantifying and weighing the reagents; wet cleaning the rock; synthesis, application, and removal of the plaster. Throughout the research, analysis techniques were employed to characterize the starting materials, the products formed, and the alterations produced on the rock surface. After the wet cleaning process, there was a trend for increased brightness in all studied ranges, and an increase in brightness in all ranges where 100% kaolin plaster was applied during 7 and 14 days.