Application of ground penetrating radar on Colloseum pillars

One very important aspect in restoring monuments is to determine the decay degree of the material forming their structures. To this end three pillars of Colosseum consisting of travertine blocks have been investigated by Ground Penetrating Radar (GPR), in order to test the efficency of various measurement technique and to obtain information on geometry and fracturing monument structural elements. Mesaurements were made each 5 cm, on horizontal and vertical profIles over some faces of investigated pillars. In order to improve resolution and interpret the reflections obtained, seismic-type processing using deconvolutions, filtering in frequency and in wavenumber, migrations etc. has been applied. In parallel, a specific processing programme for SIRlO (Radan III) and a programme of seimic processing have been used. Among various methods applied, the best result have been obtained using FK velocity filter on stack sections. A detailed geometric tridimensional reconstruction of pillars, starting from external geometry, has been allowed us to directly correlate external discontinuity with sigle electromagnetic events. The working procedure has given detailed information on blocks internal geometry and on presence of unknown voids and fractures. This esperimental study has confirmed the efficency of radar in identifying discontinuities in construction elements. Once again, the inadequacy of standard radar processing programmes has been highlighted.