A study of reusable electromechanical impedance methods for structural health monitoring of civil structures

Tawie, Rudy; Na, S.; Lee, Haeng‐Ki

doi:10.1117/12.2010077

Cited by 1 publication

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, the observations are consistent to that reported by Soh and Bhalla (2005), who theorized that the relative shift of piezo peak as compared to 'free-free' condition essentially reflected the gradual gain in the strength of concrete caused by hydration of concrete (Lee and Tawie, 2009;Tawie et al, 2013). Similar behaviour of these sensor types was observed for Specimens 2 and 3, as can be observed from Figures 7 and 8 for both early hydration and long-term hydration monitoring.…”

Section: Statistical Analysis Of Conductance Signaturessupporting

confidence: 89%

“…28 day of curing), the RMSD results were plot for 28 days only. In general, for all the three configurations, initially sharp peaks were observed at the PZT patch's resonant frequencies, which flattened (coupled with up/down and lateral shifting) with the passage of time, when concrete transitioned from the plastic to the hardened state (Lee and Tawie, 2009;Lim, 2014;Tawie et al, 2013). Large shifts in signatures were observed during the first 40 h. After that, the shifts were very gradual, indicating that concrete attains most of its stiffness during the initial hours followed by nominal changes.…”

Section: Statistical Analysis Of Conductance Signaturesmentioning

confidence: 99%

See 1 more Smart Citation

Development and evaluation of an external reusable piezo-based concrete hydration-monitoring sensor

Moharana

Bhalla

2019

Journal of Intelligent Material Systems and Structures

View full text Add to dashboard Cite

Hydration of concrete is a very complicated and multiphase process, where the cement gel transforms into a hardened state from plastic/semiplastic phase. Proper progression of the hydration process ensures the development of targeted mechanical properties such as the elastic modulus, the coefficient of thermal expansion, the Poisson’s ratio, and finally, the characteristic strength of concrete. Concrete experiences large thermal variations during the early phase of hydration due to the heat generated during the formation of cement hydration compounds, which contributes to shrinkage and cracking, somewhat making ground for the ultimate failure in the long run. Therefore, it is utmost important to monitor the progression of hydration for enhancing performance during the curing and the early service life. This article presents a new reusable external configuration of piezo-impedance transducers to monitor the hydration process in concrete structures using the electro-mechanical impedance technique. The proposed configuration consists of a thin metal foil instrumented with piezoelectric ceramic patch at the free end with the other end of the foil embedded inside the concrete. This configuration is compared against a piezoelectric ceramic patch directly bonded on the rebar used for reinforcement and another one embedded in the concrete surrounding the rebar. The sensing capability of the proposed metal foil configuration is clearly evident from the coupled admittance signature quantitatively vis-à-vis the other configurations. As a preliminary analysis, root mean square deviation values are employed to monitor the hydration process quantitatively. A piezo-equivalent mechanical model is also developed wherein the piezo-identified mass, stiffness and damping parameters are investigated for the cement hydration process so as to chalk out rigorous quantifiers of hydration progression. The employability of the proposed configuration is further proven by explanation of the physio-chemical products developed during various stage of hydration with step-by-step explanation along with corelation of the piezo-identified mass, stiffness and damping parameters. Overall, the proposed reusable configuration carries a high potential for field deployment in concrete industry for early detection of physio-chemical changes.

show abstract

Section: Statistical Analysis Of Conductance Signaturessupporting

confidence: 89%

Section: Statistical Analysis Of Conductance Signaturesmentioning

confidence: 99%