Field exposure sites and accelerated laboratory testing of marble panels

The use of thin marble and limestone for facade cladding has increased substantially during the last five decades. The durability of thin slabs (often only 30 mm thick) has been assumed to be satisfactory based on centuries of successful use as a structural building stone. Nevertheless, all over the world, the long term deformation and strength loss of some claddings have led to concerns about its safe and durable use. The detailed assessment of marble and limestone within TEAM (see also www.sp.se/building/team) is used to develop a hypothesis for the observed deterioration and to develop remedial actions. This paper describes the field exposure sites, the accelerated test, and presents parts of the results. The results indicates that all marbles bow, but at different magnitudes. The marbles demonstrate diurnal and seasonal variation in bowing and dependence on the thickness and impregnation. The final evaluation of the results will be presented in 2005.