53 - Mechanical and Acoustic Emission characterization of lime-based masonry constituents.

This paper deals with an improved representation of the progression of damage in lime-based masonry under cyclic loads using the Acoustic Emission (AE) technique. Stress-strain relations are a familiar concept in engineering which detail the elastic-plastic behaviour of the material. During AE monitoring, AE activates with the increase of stress and initiation of micro fracture due to local changes in the material structure. The population of AE events registered at an increasing stress levels provides information on the structure's integrity. In the present study, masonry couplets and walls were built with clay bricks in combination with two different mortar types: hybrid lime-cement (LC) and lime hydrate mortar (LH). One set of experiments focuses on masonry couplets and another set of experiments focuses on masonry walls, both under compression. The AE-based damage quantification is validated by a comparative analysis with strain measurements from Linear Variable Differential Transformers (LVDTs). In conclusion, results indicated that at initial stages the AE trend was closely related to axial strain for LC specimens and lateral strain for LH specimens. Regardless of size effects with respect to masonry couplets and walls, there was no significant difference in damage progress. [ABSTRACT FROM AUTHOR]