Influence of Ph during Chemical weathering of bricks: Long term exposure

Author(s): Inge Rörig-Dalgaard, A. Elena Charola
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference
Materials, Systems and Structures in Civil Engineering 2016 segment on
Historical Masonry
Editor(s): Inge Rörig-Dalgaard and Ioannis Ioannou
ISBN: 978-2-35158-178-0
e-ISBN: 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 178-187
Total Pages: 10
Language : English

Abstract: Within the framework of environmental weathering of bricks in historical structures, this study
focuses on new bricks currently employed for restoration projects. The bricks were subjected
to an accelerated chemical weathering test by immersion in solutions with pH ranging from 3
to 13 for different lengths of time up to 432 days, data to 288 days are presented since the
project is still ongoing. The study analyzed the changes of pH induced in the solutions by the
presence of the bricks (this also served to adjust the pH to the intended value), as well as the
concentration of various ions extracted from the bricks over time. As the bricks were taken out
at the different times, their capillary absorption curves were determined, followed by a vacuum
saturation with water for the determination of the open porosity, as well as the density. Finally,
a 24 hour total immersion in water was also carried out proving to be practically the same as
achieved after the capillary absorption rate stabilized after 6 hours in this test. The results
obtained showed that the two main deterioration mechanisms are the ion-exchange at acid pH,
and the alkaline corrosion undergone particularly at pH 13.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00