Towards smart concrete for smart cities: Recent results and future application of strain-sensing nanocomposites

Abstract

The use of smart technologies combined with city planning have given rise to smart cities, which empower modern urban systems with the efficient tools to cope with growing needs from increasing population sizes. For example, smart sensors are commonly used to improve city operations and management by tracking traffic, monitoring crowds at events, and performance of utility systems and public transportation. Recent advances in nanotechnologies have enabled a new family of sensors, termed self-sensing materials, which would provide smart cities with means to also monitor structural health of civil infrastructures. This includes smart concrete, which has the potential to provide any concrete structure with self-sensing capabilities. Such functional property is obtained by correlating the variation of internal strain with the variation of appropriate material properties, such as electrical resistance. Unlike conventional off-the-shelf structural health monitoring sensors, these innovative transducers combine enhanced durability and distributed measurements, thus providing greater scalability in terms of sensing size and cost. This paper presents recent advances on sensors fabricated using a cementitious matrix with nanoinclusions of Carbon Nanotubes (CNTs). The fabrication procedures providing homogeneous piezoresistive properties are presented, and the electromechanical behavior of the sensors is investigated under static and dynamic loads. Results show that the proposed sensors compare well against existing technologies of stress/strain monitoring, like strain gauges and accelerometers. Example of possible field applications for the developed nanocomposite cement-based sensors include traffic monitoring, parking management and condition assessment of masonry and concrete structures.

Framing a Satellite Based Asset Tracking (SPARTACUS) within Smart City Technology

“…Smart city initiatives attracted the attention of many researchers and politicians on issues such as mobility, security, environment, or any combination of them, since they are driven by the goal of serving citizens in a better way [1] . Moreover, smart cities facilitate the government to monitor, understand, analyze, and plan the city in order to improve the equity, efficiency, and quality of life [2,3] . The attention of the research activity summarized in this paper is focused on the concept that the smart city development provides opportunities to enhance the quality of civil infrastructures as well.…”

Application of Nanomaterials in Production of Self-Sensing Concretes: Contemporary Developments and Prospects

“…The variation of strain or stress is associated with the variation in material's electrical characteristics, such as resistance or impedance. Therefore, it is possible to efficiently detect and localize crack formation and propagation in selected concrete element [5]. The concept of smart concrete is based on the idea from the last decade devoted to application of fibers in concretes (FRC -fiber reinforced concrete), which enabled sensing the strain by piezoresistivity or sensing damage by utilizing the relation between damage and electric resistance [6].…”

“…This is due to the remarkable mechanical and electrical properties of some nanomaterials, which make these nanoparticles ideal for manufacturing self-sensing cement-based composites [5].…”

Acceleration of percolation for cementitious sensors using conductive paint filler

“…With the need to actively monitor the health of large-scale civil infrastructure, there is a need to used with Portland cement are carbon nanotubes [3], [26], [27], carbon fibers [27], [28] and carbon black [15], [18]. Also used are materials like Piezoresistive ceramics [29].…”

“…D'Alessandro et al [3] modelled a cementitious sensor fabricated with MWCNT's and observed its response to dynamic loading. The cementitious sensors were mounted on a large beam and a dynamic load was applied.…”