STRUCTURAL INTEGRITY OF WEATHERED AND FRESHLY QUARRIED INDIANA LIMESTONE

Natural building materials, such as Indiana Limestone, are used to create desirable veneers and structural elements. These materials are exposed to weathering processes which may affect their strength. Indiana Limestone blocks were originally installed as veneers on Zook Hall at the University of Akron in 1963 and were removed from the building during a recent (2016) renovation. We collected blocks of the weathered and freshly quarried Indiana Limestone in order to determine how weathering affects the physical and mechanical properties of a common building material. Samples from both weathered and freshly quarried Indiana Limestone blocks were collected to perform density measurements and uniaxial compressive strength (UCS) and indirect tensile (IDT) tests. Density measurements were performed to characterize how the density changes from the interior of the weathered limestone to the exterior of the weathered limestone as well as natural density variations in the freshly quarried limestone. The results of the characterization show the density decreases from the interior of the weathered slab to the more weathered exterior of the weathered slab. However, the density is relatively constant across similarly sized blocks of the freshly quarried limestone. In all UCS and IDT experiments, the weathered Indiana Limestone is weaker than the freshly quarried Indiana Limestone. These strength differences are likely due to increasing porosity in the weathered material. The results indicate that Indiana Limestone will weaken when weathered and may not remain structurally sound over the expected lifetime of some structures.