Anisotropic Thermal Expansion Causes Deformation of Marble Claddings

Abstract

The investigations on hand were performed due to the increasing number of deformations on marble cladding panels on building facades caused by atmospheric influences. A special triple dilatometer was developed to measure the thermal expansion of two kinds of marble that are typically used in stonemasonry, namely white crystalline marble from Carrara and Laas (both Italy). The strong anisotropy of their thermal expansion was investigated systematically, with special consideration of residual dilatations (thermal hysteresis). In analyzing the results, it becomes evident that there is a causal relation between this anisotropy and the observed permanent deformations of marble cladding panels. Measurements of the water absorption capacity of marble after different thermal pretreatments indicate a loosening of the grain boundaries in marble caused by temperature changes. The paper concludes that the strong thermal anisotropy of marble is an important factor for the lack of durability of this building material and therefore should no longer be neglected when producing marble panels.