Synthesis and characterization of cement/carbon-nanotube composite for structural health monitoring applications

The civil structures during their useful life are subjected to different loads (environmental and mechanical), that cause progressively deterioration and that consequently requires maintenance efforts to keep them safe and operative. In this work, a novel alternative is proposed based in the development of a smart material with multifunctional characteristics that allow the Structural Health Monitoring (SHM)without requiring external sensors. This was possible by developing cement matrix compounds with the addition of carbon nanotubes. The manufacturing of this material began with an experimental design (DOE) that allowed to determine the mixtures-type with which the sensor was manufactured, additionally repeatability and reproducibility was guaranteed. To measure the piezoresistive behavior of the samples, we used an INSTRON 5582 universal testing machine, a data acquisition equipment to obtain the variation in voltage and Micron Optics SM130 optical sensing interrogator for measuring deformations. Once the rheological and mechanical behavior of the material were characterized, mechanical tests of the material were carried out without exceeding the maximum deformations of the material in order to acquire data on the resistive behavior of the structure and find the gauge factor. The results of this development offer a part of the solution to the growing needs in the field of civil engineering against the early warning of damages caused by both natural phenomena and human causes (use of inappropriate materials, wrong calculations, overloads).