Damage development to treated brick masonry in a long-term salt crystallisation test

Abstract

The development of salt-damage to brick masonry specimens, treated with a water repellent and a consolidant, during a long-term salt crystallisation test, is evaluated. The experiment performed followed the Recommendation RILEM TC 127-MS-A.1, which uses constant drying conditions 20 °C/50% RH. Due to the fact that the specimens on which, the salt crystallisation test was performed has been stored for several years under the same test conditions, repeated evaluations could be performed over time. The treatments comprised a water repellent (siloxane), a consolidant (ethyl silicate), as well as a treatment of ethyl silicate followed by siloxane. Three months was initially considered to be the end of the test, being the period in which the specimens could dry out almost completely. The damage present after 4 days, 3 months and 48 months has been compared. It was found that in the period between 3 and 48 months the damage mechanism still goes on, although nearly all water introduced as a salt solution at the start of the test had evaporated. Most damage indeed occurred in the period approximately between 12 and 48 months.