The effect of salt crystallisation on the mechanical properties of limestone: statistical correlation between non-destructive and destructive techniques

Abstract

Mokattam limestone is the most frequent building stone used in the cultural heritage buildings in Historic Cairo (Egypt) and it is susceptible to the ongoing effects of salt weathering. A purpose-made simulation chamber was used to test in the laboratory the salt weathering on limestone samples from an active quarry at Helwan area (30 km, south Cairo) at different temperature regimes (20, 30 and 40°C). To assess the extent of the resulted decay, mechanical properties of the fresh quarry and tested samples after different regimes were investigated with non-destructive techniques (P-wave velocity and Leeb rebound hardness) and destructive techniques (uniaxial compression strength). The different mechanical measurements of the tested samples were notably affected after the different temperature regimes. Uniaxial compressive strength is highly correlated with Leeb rebound hardness while P-wave velocity showed a low relevance for the prediction of the strength of the tested samples.