On the use of eggshell lime and tuffeau powder to formulate an appropriate mortar for restoration purposes

Abstract

AbstractPreservation of cultural heritage, especially historic monuments, is a vital task. In addition, waste recovery is an essential goal of sustainable development. In this study the properties of a food waste, eggshells, and a quarry waste, powder obtained from stone-extraction operations, are evaluated in terms of their possible use in restoration mortar.An excellent lime has been developed based on eggshell calcination. A lime-based mortar exclusively composed of this eggshell lime and tuffeau powder was developed and characterized in order to demonstrate its compatibility with restoration works. To pursue this objective, microstructural, physical and mechanical properties were investigated and compared to those of the tuffeau limestone.The tested formulation using tuffeau powder was found to meet compatibility requirements up until the hygrometric environment lowered the water content of the mortar. The desiccation of the mortar can then generate shrinkage cracks leading to mortar crumbling. As a consequence, hygrometric susceptibility of the mortar is an essential parameter to be investigated in order to study the durability of lime-based mortars made out of limestone powder.