Strength development monitoring and dynamic modulus assessment of cementitious materials using EMI-Miniature Prism based technique

摘要

Electromechanical impedance (EMI) technique provides an alternative means of characterizing strength development of early age concrete on a real-time basis. However, most existing studies employing the technique heavily rely on statistical tools for strength development characterization. This article proposes a new impedance-based approach to strength and dynamic modulus assessment of cementitious materials. In this approach, a lead zirconate titanate patch is surfaced-bonded on a customized cementitious material specimen, known as 'Miniature Prism', in which the conductance signatures throughout the curing process are acquired. A 3D coupled field finite element (FE) model is then developed to compute the conductance signatures and model updating is performed using the experimental results. The conductance signatures computed by the updated FE model are found to be in good agreement with experimental results. The key contribution of this approach is the use of 'Miniature Prism' which ensures consistency of the resonance peaks in the conductance spectrum between identical specimens. This has been very difficult, if not impossible, to achieve with the conventional EMI technique. This merit allows for modelling of the electromechanical system and hence parametrically predicting the dynamic modulus of elasticity of the cementitious material throughout the curing process. Comparative study is also conducted on various conventional and advanced techniques and results indicate that the proposed technique is effective in strength assessment of cementitious materials. In addition, the technique is suitable for autonomous online monitoring purpose, and thus exhibits promising potential to substitute the conventional non-destructive testing methods.