Testing historical recipes with organic additives to alter the water absorption of traditional lime mortar

Abstract

This research aims to investigate the effect of organic additives on the properties of hydraulic lime mortars, primarily focusing on water absorption properties and freeze-thaw durability. Four organic additives are selected based on historical mortar recipes from different European sources dating back to the 17th, 18th and 19th century. These additives are linseed oil, egg white, ghee (Indian clarified butter) and oxblood. Basic hydraulic lime mortars have been gauged with the respective additives in different quantities. The analysis include open porosity, capillary water absorption, and effects of freeze-thaw tests. To gain insight on the effectiveness of the organic additives in mitigating freeze-thaw action due to less water absorption, these results are applied to assess the durability of the different mortars, which is physically tested in a freeze-thaw experiment. The use of ghee shows promising results.