State-of-the-art of construction stones for masonry exposed to high temperatures

The consequences of fires on cultural heritage building and monuments can be deleterious, as historic and recent cases demonstrate. In particular, devastating fires have ravaged stone masonry monuments, which must be properly repaired and retrofitted with rational, performance-based design. Updated quantitative knowledge and design tools - especially about materials' properties - is necessary to implement such performance-based strategies. Under this perspective, the paper takes into account a number of references to present a state-of-the-art about the current knowledge of high-temperature behaviour of different families of construction stones - namely granites, marbles, sandstones and limestones. The stones' strain behaviour, thermal properties (conductivity and specific heat) and mechanical properties (compressive strength, elastic modulus, peak compressive strain, Poisson's ratio and tensile strength) are accounted for. The residual mechanical properties, i. e. after high temperature exposure, are under particular consideration in view of evaluating the residual structural reliability of stone masonry structures after a fire with numerical methods. The micro- and macroscopic level are put into relationship, linking the information about the chemical and physical transformation of component minerals under high temperatures to the changes in the stones' properties and thermal strain. The aim is to provide quantitative information, namely mean values and intervals of confidence, for the considered properties to be appliable in the performance-based fire design and evaluation of stone masonry structures.