A CASE-STUDY OF THE PROPERTIES OF MARBLE AS BUILDING VENEER

This study brings together documentation of two separate properties of one marble--thermal anisotropy and residual strain. The data focuses on a major building in which.31 % of the panels developed bows with amplitudes up to 3 cm after 17 years and the tensile strength degraded by an average of 25%. The magnitude of bowing and strength loss were found to be directly proportional. Bowing was determined to be the result of grain-boundary damage due to the thermal anisotropic character of calcite through laboratory thermal cycling for over 600, 24 hour cycles. This resulted in a loss of tensile strength. All panels were found to release residual strain when overcored, with the amount generally increasing as thermal cycling progressed. It is hypothesized that following the loss of strength, residual strain was released from the calcite. The net result these two processes was an elongation of the panels. The constraint of the panel anchors prevented accommodation of this increased length with the result that bows developed. Inelastic bowing further reduced the panel strengths.