Carbon nanotube reinforced mortar as a sensor to monitor the structural integrity of restored marble epistyles under shear

Metallic "I"-shaped connectors, properly placed in sculptured grooves, are used nowadays for restoring damaged connections of the Parthenon Temple. The grooves are then filled with a suitable cement mortar. In this study, the mortar was reinforced with multi walled carbon nanotubes, in an effort to develop a smart material which could monitor the structural integrity of the connection, by measuring its electrical resistance through the Electrical Resistance Change (ERC) technique. The connection was subjected to shear using a properly designed metallic restraining-loading system. The ERC technique was used in conjunction with traditional (electrical strain gauges and clip gauges) and innovative sensing techniques (Digital Image Correlation and Acoustic Emission). The data obtained by the ERC technique are in very good qualitative agreement with the respective ones provided by both the traditional and the innovative techniques. Moreover, the overall variation of the ERC is well compatible with the load applied, indicating that the specific quantity could be a flexible tool for monitoring strain/damage of the restored connections. Copyright (C) 2016 The Authors. Published by Elsevier B.V.