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In order to achieve effective monitoring of concrete structures for sound structural health, the addition of carbon nanotubes (CNTs) into cementitious materials offers a promising solution for fabricating CNT-modified smart concrete with self-sensing ability. This study investigated the influences of CNT dispersion method, water/cement (W/C) ratio, and concrete constituents on the piezoelectric properties of CNT-modified cementitious materials. Three CNT dispersion methods (direct mixing, sodium dodecyl benzenesulfonate (NaDDBS) and carboxymethyl cellulose (CMC) surface treatment), three W/C ratios (0.4, 0.5, and 0.6), and three concrete constituent compositions (pure cement, cement/sand, and cement/sand/coarse aggregate) were considered. The experimental results showed that CNT-modified cementitious materials with CMC surface treatment had valid and consistent piezoelectric responses to external loading. The piezoelectric sensitivity improved significantly with increased W/C ratio and reduced progressively with the addition of sand and coarse aggregates. 

Fiber Bragg grating (FBG) sensors have been applied to assess strains, stresses, loads, corrosion, and temperature for structural health monitoring (SHM) of steel infrastructure, such as buildings, bridges, and pipelines. Since a single FBG sensor measures a particular parameter at a local spot, it is challenging to detect different types of anomalies and interactions of anomalies. This paper presents an approach to assess interactive anomalies caused by mechanical loading and corrosion on epoxy coated steel substrates using FBG sensors in real time. Experiments were performed by comparing the monitored center wavelength changes in the conditions with loading only, corrosion only, and simultaneous loading and corrosion. The theoretical and experimental results indicated that there were significant interactive influences between loading and corrosion for steel substrates. Loading accelerated the progress of corrosion for the epoxy coated steel substrate, especially when delamination in the epoxy coating was noticed. Through the real-time monitoring from the FBG sensors, the interactions between the anomalies induced by the loading and corrosion can be quantitatively evaluated through the corrosion depth and the loading contact length. These fundamental understandings of the interactions of different anomalies on steel structures can provide valuable information to engineers for better management of steel structures. 

Carbon‐based nanoparticles are widely regarded as promising nanofillers in nanocomposites to pursue advanced properties. To date, there has been a lack of systematic investigation into the structural variations of nanofillers and their influences on dispersion characteristics, as well as the resulting mechanical properties of nanocomposites. In this study, nanodiamond (ND), carbon nanotube (CNT), and graphene (GNP) were selected as the representative zero‐, one‐, and two‐dimensional nanofillers, respectively. A novel functionalization technique utilizing carboxymethyl cellulose (CMC) was employed to disperse nanofillers. The various characterization techniques and experimental results revealed that CMC functionalization was effective in reducing the agglomeration and improving the distribution uniformity of all three nanofillers. Among the three nanofillers, zero‐dimensional ND exhibited the most homogeneous dispersion quality in epoxy nanocomposites. The strongest abrasion resistance was found in ND‐reinforced epoxy nanocomposites, while CNT‐reinforced epoxy nanocomposites exhibited the best tensile properties.

Nanodiamond with a spherical structure had better dispersion characteristics.

Cylindrical carbon nanotube and planar graphene tended to agglomerate.

Nanodiamond reinforced nanocomposites had better abrasion resistance.

Carbon nanotube reinforced nanocomposites had better tensile properties.

Carboxymethyl cellulose functionalization was valid for all three nanofillers.