Recently, Structural Health Monitoring (SHM) has become a paramount issue for the construction and infrastructure sectors. In developed countries, the maintenance and repairing costs of concrete structures are around 3-4% of gross national product, but inspections are still the preferred activities even if they are discontinuous, punctual, and most of the time late with respect to the damage showing up. On the contrary, monitoring techniques enable continuous data acquisition and analysis, can be applied in parallel to several portions of the structure, and are unquestionably useful for a prompt and timely intervention.

In this regard, non-destructive techniques (NDTs) should be preferred as they enable monitoring without damaging the structure. Electrical resistivity (or impedance) measurement is the most used NDT, because of its relative ease, fast performance, and its predictive power related to concrete durability. It can be used for determining water and chloride penetration, carbonation, presence of cracks or load variations, and many other factors. Generally, concrete has a high electrical resistivity, which makes the monitoring of structures difficult because of the necessity of expensive instrumentation. For this reason, to increase concrete electrical conductivity and enhance self-sensing and piezoresistive properties, conductive fillers and fibers can be added to the mix design, allowing the use of low-cost measurement devices. Self-sensing is the ability of a material to sense its own condition, including strain, stress, damage, and temperature, whereas piezoresistivity is a physical characteristic of electrically-conductive materials, which leads to a variation in the electrical resistivity of the material subjected to strain. Several conductive additions can be added to concrete, such as steel or carbon fibers, carbon nanotubes, graphene nanoplatelets, graphite powder, carbon coke, carbon black, etc., which besides being able to ease the current flow can also improve the mechanical and durability properties of concrete by refining its pore structure.

The purpose of this Special Issue is to publish original research and review articles on the recent advances in the design and optimization of cement-based mixtures using conductive additions to improve the mechanical strength of the materials, the self-sensing ability and durability of structures, and/or their monitoring by means of NDTs with innovative or conventional devices.

Potential topics include but are not limited to the following:

• Self-sensing materials
• Conductive fillers
• Conductive fibers
• Durability
• Non-Destructive Techniques (NDTs)
• Diagnostic methods and structural health monitoring (SHM)
• Electrical resistivity
• Electrical impedance
• Piezoresistivity
• Innovative measurement devices for SHM
• Case studies dealing with NDTs in civil engineering