The main reasons for deterioration of bricks are frost, crystallization pressure and chemical exposure. Despite of this the effect of chemical exposure is limited clarified. Depending on the brick type the original pH of bricks are 9-10. Though bricks can to subjected to water in shape of acid rain with a pH as low as 3. The exposure of acid rain and rain water to bricks is expected to have an influence on the brick matrix dependent on the specific exposure but to which extend? The present work is a systematic test of the influence of the pH on the brick matrix where the effect of water with different well-defined pH values are examined to investigate the long term effect of acid rain or other reasons causing pH changes to bricks (as e.g. electrokinetic treatment). Through capillary suction, macro pictures from the exposed surfaces, measurement of the pH and electrical conductivity it seemed that there is a consistence with the literature of the glassy phase describing ion exchange at low pH and break down of the lattice in the glassy structure at high pH. At present remains examination of polished sections with SEM/EDX, measurements of each of the ionic contents in the brick matrix and new series with a longer exposure time to make more sound conclusions. This work is ongoing.
Proceedings of the 9th International Masonry Conference, 2014