Temperature and moisture effects on electrical resistance and strain sensitivity of smart concrete

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

“…Moreover, even if the cementitious substrate is wet or contains ions (for example deriving from de-icing salts), sensors electrical response is not influenced by environmental conditions. On the contrary, when CNTs are directly immersed in the bulk cementitious matrix, the surrounding environment directly influences sensing ability [26][27][28][29].…”

“…However, even if the electrical conductivity of cementitious materials is significantly increased while maintaining or even improving their mechanical properties, their implementation is limited due to several environmental factors (such as humidity and temperature) affecting the measurement [26][27][28][29][30]. Moreover, the huge amount of fillers to be used in the bulk matrix as well as, the potential toxicity of functionalized CNTs when mixed on-site [31], discourages their diffusion.…”

Self-Sensing Alkali-Activated Materials: A Review

“…For metakaolin AAM, it was reported by MacKenzie and Bolton [87] that as the temperature increased up to 80 °C the resistance of the sample started to increase as well due to the depletion of water in the matrix. On the contrary though, in an OPC based investigation conducted by Demircilioglu et al [139] under sealed conditions the resistance of the sample between 50-115 °C remained fairly constant due to the equilibrium of water vapor as a result of the sealed environment. Similarly, in another OPC based application under sealed conditions Teomete [151] reported small changes in resistance between 50 °C up until 200 °C.…”

“…The first region of temperature sensing of reported applications is situated approximately between -30 • C up to around 50 • C. This section encapsulates most of the temperature sensing tests that have been carried out and corresponds to the majority of field and civil engineering applications. The behaviour for this temperature range is fairly straightforward as when the temperature increases, the resistance of the material decreases [24,26,27,65,87,131,139,[148][149][150].…”

“…The influence of additional factors such as moisture and temperature on strain performance have not yet been accounted for in AAM apart from certain niche applications [22]. In comparison, the effects of moisture [138,139] and temperature [140] on OPC strain sensing have already been reported. While the literature available is fairly limited, it can be viewed that metakaolin and ground granulated blast furnace slag based AAM have the potential of showcasing high sensing capabilities compared to fly ash AAM.…”