Felicity ratio as a fingerprint of the thermal-induced decay on a Portuguese granite

Abstract

Granite is a natural stone widely applied in heritage and modern buildings in Portugal and changes in temperature extremes, that leads to wildfires, leverages the importance of thermal induced ageing study of this type of stones. The results of an experimental work based physical and mechanical characterization of a Portuguese granite subjected to thermal ageing are presented. During two stages of uniaxial compression test (loading/unloading and failure), acoustic emissions were monitored. A decrease with increasing temperature in apparent density, ultrasonic velocity, compressive strength , and an increase in porosity was observed, which is in line with stereomicroscope and scanning electron microscope images. Acoustic emission analysis shows the influence of thermal ageing in failure mechanism and pure Kaiser effect was not observed. With increasing temperature, Felicity ratio decreases showing that this parameter can be applied for thermal-induced decay characterization. • Granite decay under high temperature was studied through Acoustic Emission (AE). • Strong relation between physical and mechanical parameters and Felicity ratio. • Temperature influences granite failure mechanism. • Temperature Increase induced earlier initial and unstable crack propagation. • Felicity ratio is a fingerprint for granite thermal-induced decay.