Chemical Characterization of Lime-Based Binders in Historic Buildings of Latvia

The aim of this research is to investigate the chemical composition of stone materials of several local historic buildings with a purpose of elaboration of restoration strategy, including the choice of restoration materials. Most of the examined mortars are lime-based hydraulic mortars, characteristic of the architecture of 19th/20th century. Pure aerial lime binders show reduced compatibility with historic materials, that is why lime binders with pozzolan additive (cement) are an appropriate choice for restoration. In order to examine the changes of hydraulicity (i.e. the property of binders to harden when exposed to water) of perspective restoration binders, a series of blended lime-cement mixtures were synthesized with growing content of cement (up to 10 % by weight). A significant relationship between cement content and hydraulic properties has been shown.