Influences affecting compressive strength of modern non-hydraulic lime mortars used in masonry conservation

摘要

Non-hydraulic lime based mortars are currently more and more often used for the repair of historic masonry. They are presumed to be compatible with the original mortar/masonry and their properties are not always evaluated, mainly due to a lack of research into mortars produced in a traditional manner. Influences of curing conditions, quality of mixing and water content on compressive strength of a non-hydraulic lime mortar mix made of lime putty were reviewed and examined. The mortar specimens were prepared with various water contents, cured in outdoor and indoor conditions and tested after 1, 2, 4 and 6 months. Phenolphthalein pH indictor was used to measure the carbonation depth. The strongest mortar specimens were from the indoor ageing condition although the mortar was less carbonated. The addition of water into the fresh mix increased porosity and lowered the compressive strength, however there were other influences which affected this relationship.