Comparison of Field Testing with Laboratory Testing of the Durability of Stone

Abstract

Abstract Samples of three granites (Texas Pink, Mount Airy White, Academy Black), one marble (Carrara) and Indiana Limestone have been exposed to 11 years of natural weathering on the roof of a building in the Chicago area. Twice a year, the samples are visually reviewed. In addition, the changes in physical properties have been monitored using non-destructive test procedures for determination of the dynamic (sonic) modulus of elasticity. The sonic modulus measurements were recorded using procedures as outlined in ASTM C 215, “Standard Test Method for Fundamental Transverse, Longitudinal, and Torsional Frequencies of Concrete Specimens.” The sonic modulus measurements were compared to measurements of similar stone samples that were exposed to laboratory accelerated weathering testing. The exposed and protected surfaces have recently been examined petrographically, and the changes due to the natural weathering recorded. Based on this additional testing and evaluation, conclusions can be drawn which further indicate the use of accelerated weathering. Testing can effectively evaluate the long-term changes in the mechanical and physical properties of dimension stone when exposed to natural weathering.