A Decision Process Implementation for Microwave Near-Field Characterization of Concrete Constituent Makeup
Determination of concrete compressive strength is one of the most important factors in the construction industry. Concrete is a mixture of cement, water, sand (fine aggregate) and rock (coarse aggregate) of various sizes. Water and cement chemically bind to form the cement paste phase of concrete, which primarily influences the compressive strength. The aggregate content mainly acts as a filler but also influences the compressive strength of concrete. Currently, there is no single method for nondestructive determination of compressive strength of concrete. As a result, the only reliable method of compressive strength measurement is to core a specimen from an existing structure and perform a compressive failure test. In recent years, studies on the reflection properties of concrete with varying material content have been performed using microwave nondestructive testing techniques. These techniques, employing open-ended rectangular waveguide probes, have shown tremendous potential for determining concrete constituent makeup. The results have demonstrated that microwave reflection property measurements of concrete as a function of varying constituent makeup, possess statistical properties that provide for a unique fingerprint . In this paper a simple decision process is proposed, based on the maximum likelihood ratio, which uses the a priori statistical distribution of microwave reflection measurements for material content determination of concrete specimens. The results show that by simply performing two sets of microwave reflection property measurements at 3 and 10 GHz, the constituent makeup of an unknown concrete specimen can be very closely determined. Subsequently, the compressive strength of the specimen could be easily determined from a simple lookup table relating constituent makeup and compressive strength, which are readily available in the industry.
K. J. Bois and R. Zoughi, "A Decision Process Implementation for Microwave Near-Field Characterization of Concrete Constituent Makeup," Subsurface Sensing Technologies and Applications: Advances and Applications in Microwave and Millimeter Wave Nondestructive Evaluation, Springer-Verlag, Oct 2001.
The definitive version is available at http://dx.doi.org/10.1023/A:1013264900715
Electrical and Computer Engineering
Electric Power Research Institution
National Science Foundation (U.S.)
Keywords and Phrases
Concrete; Maximum-Likelihood; Microwave Nondestructive Testing; Infrastructure Testing and Cement-Based Material Evaluation; Material Characterization
Article - Journal
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