Use of geomechanical research in the conservation of stone monuments (Maadi Town Temple, Fayoum, Egypt)

Maadi Town Temple was discovered by Prof. Villiano of Milan University in 1936, during excavation work in the Maadi Town area of the Fayoum Province. Since this discovery there has been no scientific ally based conservation of the monument, often than some unsuccessful restoration. The ruins were left uncovered and exposed to climatic deterioration until 1994, when scientific members of the Faculty of Archaeology of Cairo University undertook a study of the degradation processes affecting the Temple. This started with field-based observation of the monument's condition and, description of the building materials, (limestone and mortar). In 1997 samples of the building material were collected on site and in 1998 laboratory studies of those samples were carried out in the Department of Geomechanics at the Warsaw University. The laboratory studies comprised two main steps: diagnosis of the deterioration factors and their geomechanical interpretation as an effect of salt solution, water saturation and temperature changes. The behaviour of building limestone and mortar were considered relative to their mineralogical composition, internal structure and path of deformation. In laboratory testing two geomechanicalmethods were used: non- destructive ultrasonic control and destructive uniaxial compression testing with monitoring of prefailure and postfailure deformation fabrics. Both appliedmethods showed the salt solutions to be themain deterioration factor affecting the stone elements and the anisotropy and various properties of themortar and of the bedded limestone as themain factors destabilising the construction of the Temple as a whole. Degradation occurs gradually due to the internal and external inhomogeneous field of deformation caused by climatic changes, with cyclic strengthening due to salt incrustation and subsequent softening after water saturation and temperature changes.