Microwave NDE Method for Health-Monitoring of Concrete Structures Containing Alkali-Silica Reaction (ASR) Gel
The presence of reactive aggregates combined with sufficient moisture and concentration of alkalis are the three basic requirements for damage due alkali-silica reaction (ASR) gel formation and expansion in concrete. For health-monitoring of concrete structures, and in order to investigate the potential for detecting ASR gel formation in existing structures, one potential technique involves studying changes in the temporal complex dielectric constant of concrete structures. In this paper, a microwave nondestructive testing approach is proposed which involves soaking two hardened mortar samples and measuring the change in their temporal complex dielectric constant in order to distinguish between the sample containing ASR gel and the one devoid of it. Part of the free water becomes bound in the sample containing ASR gel and since a portion of the microcracks in this sample contain ASR gel, the rate of evaporation of water of the two samples is expected to be different. The complex dielectric constant of the samples is significantly dependent upon the volumetric level and movement (in and out of the samples) of free water. Therefore, studying the relative different temporal rate of change in this parameter is expected to yield information about the presence or absence of ASR gel.
A. Hashemi et al., "Microwave NDE Method for Health-Monitoring of Concrete Structures Containing Alkali-Silica Reaction (ASR) Gel," Proceedings of the 40th Annual Review of Progress in Quantitative Nondestructive Evaluation, Incorporating the 10th International Conference on Barkhausen and Micro-Magnetics (2013, Baltimore, MD), vol. 1581, pp. 787-792, American Institute of Physics (AIP), Jul 2013.
The definitive version is available at https://doi.org/10.1063/1.4864901
40th Annual Review of Progress in Quantitative Nondestructive Evaluation, Incorporating the 10th International Conference on Barkhausen and Micro-Magnetics (2013: Jul. 21-26, Baltimore, MD)
Electrical and Computer Engineering
Keywords and Phrases
Characterization; Concrete Aggregates; Concrete Buildings; Concrete Construction; Concretes; Dielectric Properties; Silica; Alkali-Silica Reaction; Cement Based Material; Complex Dielectric Constant; Existing Structure; Materials Characterization; Microwave Non-Destructive Testing; Potential Techniques; Reactive Aggregate; Nondestructive Examination; Alkali-Silica Reaction (ASR); Cement-Based Materials; Microwave Nondestructive Testing
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