Smart InfrastructureMonitoring through Self-Sensing Composite Sensors and Systems: A Study on Smart Concrete Sensors with Varying Carbon-Based Filler

Structural Health Monitoring allows an automated performance assessment of buildings
and infrastructures, both during their service lives and after critical events, such as earthquakes or
landslides. The strength of this technology is in the diffuse nature of the sensing outputs that can
be achieved for a full-scale structure. Traditional sensors adopted for monitoring purposes possess
peculiar drawbacks related to placement and maintenance issues. Smart construction materials,
which are able to monitor their states of strain and stress, represent a possible solution to these
issues, increasing the durability and reliability of the monitoring system through embedding or the
bulk fabrication of smart structures. The potentialities of such novel sensors and systems are based
on their reliability and flexibility. Indeed, due to their peculiar characteristics, they can combine
mechanical and sensing properties. We present a study on the optimization and the characterization
of construction materials doped with different types of fillers for developing a novel class of sensors
able to correlate variations of external strains to variations of electrical signals. This paper presents the
results of an experimental investigation of composite samples at small and medium scales, made of
cementitious materials with carbon-based inclusions. Different from a previous work by the authors,
different carbon-based filler composite sensors are first compared at a small cubic sample scale and
then tailored for larger plate specimens. Possible applications are in the strain/stress monitoring,
damage detection, and load monitoring of concrete buildings and infrastructures.