Applications of Cement-Based Smart Composites to Civil Structural Health Monitoring: A Review

Abstract

In recent years, cement-based smart composites (CSCs) doped with conductive filler have attracted increasing research interest because of their high potentiality as self-sensing materials for civil Structural Health Monitoring (SHM) applications. Nevertheless, several issues are still open and need further studies. This paper presents an extensive state-of-the-art in which investigations on CSCs are summarized and critically revised, with the primary aim of outlining the main limits and development points. The literature review first addresses in detail several specific issues related to fabrication and operation as sensing elements of CSC samples. State-of-the-art applications of CSCs to SHM of reduced-, medium- and full-scale structural prototypes are extensively reviewed afterwards, resulting in a database useful to critically revise the main trends and open issues of the research in this field.

Real-time monitoring of structures under extreme loading using smart composite-based embeddable sensors

“…The sampling frequency of five samples/second was chosen to record the electrical resistance data. Since the direct current (DC) measurement technique is highly influenced by the polarization effect (Azhari and Banthia, 2012; Cassese et al, 2021; Rao et al, 2021), measurement was done after stabilization. Three specimens with same MWCNT concentration were tested and the average value (considering consistent data) was taken as the electrical resistance for the corresponding specimen type.…”

“…Further addition of CNT in matrix (to 0.5 wt.%) leads to further reduction in the separation distance among CNTs, subsequently, the tunneling barrier is reduced and CNTs start to come into contact with each other and form a continuous conductive network. The formation of a large number of conductive networks in the cement matrix demonstrates the extremely low resistivity of composites that falls into conducting zone (C) (Azhari and Banthia 2012; Cassese et al, 2021; Ding et al, 2019; Sanati et al, 2018). However, further incorporation of CNTs did not considerably affect the electrical conductivity of cementitious composites.…”

“…The smart cementitious composites exhibit inherent self-sensing and damage monitoring capabilities, and are fabricated by introducing conductive functional fillers such as carbon nanofibre (CNF), carbon nanotube (CNT), steel fibre, carbon black (CB), etc. into cement matrix (Demircilioglu et al, 2020; Armoosh et al, 2022; Cassese et al, 2021; Castañeda-Saldarriaga et al, 2021; Cui et al, 2017; D’Alessandro et al, 2021; García-Macías et al, 2017; Han et al, 2015, 2017a; Khushnood et al, 2019; Majumder et al, 2008; Najafishad et al, 2020; Sanati et al, 2018; Ubertini et al, 2014a; Wen and Chung, 2001a). Their unique capability of change in electrical resistance under external disturbance or loading termed as ‘ piezoresistivity ’ offers a large scope as embeddable sensors for strain, stress, crack or damage monitoring of smart concrete structures (Cassese et al, 2021; D’Alessandro et al, 2021; García-Macías et al, 2017; Han et al, 2017a).…”

“…Their sensing efficiency was estimated by calculating a constant known as ‘gauge factor’. This gauge factor shows the linear correlation between change in electrical resistance with applied strain (Cassese et al, 2021; Castañeda-Saldarriaga et al, 2021; Cui et al, 2017; D’Alessandro et al, 2021; García-Macías et al, 2017; Han et al, 2017b). It has been found that the sensing capability of smart cementitious composite depends on several important parameters such as concentration of CNTs (Han et al, 2012; Rao et al, 2020, 2021), the surface modification of CNTs (Li et al, 2007), the process involved in the dispersion of CNTs (Azhari and Banthia, 2012; Konsta-Gdoutos et al, 2014; Tian et al, 2019), nature of applied load (Yoo et al, 2018a) and measuring techniques (Zhang et al, 2017).…”

Ultraductile Cementitious Structural Health Monitoring Coating: Waterborne Polymer Biomimetic Muscle and Polyhedral Oligomeric Silsesquioxane‐Assisted C‐S‐H Dispersion

“…The hydration product and the conductive material only trigger adhesion through the conjugated hydrogen bond of the hydroxyl groups. [ 12 ] Therefore, the toughening of cement‐based sensors has the potential for optimization.…”