Characterization of cement-based materials using microwave reflection and transmission measurements

11th International Symposium on Nondestructive Characterization of Materials -- JUN 24-28, 2002 -- BERLIN, GERMANYWOS: 000185641800050The results of measurement of reflection and transmission properties of mortar and concrete specimens at their early stage (1-10 days) obtained by using a simple and an inexpensive measurement system at microwave frequencies (X-band) are presented. Dependencies of the reflection and transmission signals on time, thickness and water-to-cement ratio of the specimens are demonstrated. It is shown that the cement-based materials can be characterized by the amplitudes of reflection and transmission signals together with thickness of the specimens.Fed Inst Mat Res & Testing, Johns Hopkins Univ, Ctr Nondestruct Evaluat, Deutsch Gesell Zerstor Freie Pruf e

Characterization of cement-based materials using microwave reflection and transmission measurements

The results of measurement of reflection and transmission properties of mortar and concrete specimens at their early stage (1-10 days) obtained by using a simple and an inexpensive measurement system at microwave frequencies (X-band) are presented. Dependencies of the reflection and transmission signals on time, thickness and water-to-cement ratio of the specimens are demonstrated. It is shown that the cement-based materials can be characterized by the amplitudes of reflection and transmission signals together with thickness of the specimens

Measurement and monitoring of microwave reflection and transmission properties of cement-based specimens

The results of measurement and monitoring of reflection and transmission properties of cement-based specimens (blocks of mortar, concrete) obtained by using a simple and an inexpensive measurement system at microwave frequencies (X-band) are presented. Dependencies of the reflection and transmission coefficients on water-to-cement (w/c) ratio, preparing and curing conditions of the specimens are demonstrated. It is shown that the amplitudes of reflection and transmission coefficients, together with thickness of the specimens, determine the complex dielectric permittivity of the hardened cement-based specimens. The expected applications of the results for the determination of physical properties of cement-based materials are discussed. The causes and effects of measurement errors and uncertainties are also discussed

Measurement and monitoring of microwave reflection and transmission properties of cement-based specimens

The results of measurement and monitoring of reflection and transmission properties of cement-based specimens (blocks of mortar, concrete) during long time of their service lives, including hydration process, and different curing conditions at microwave frequencies (X-band) are presented A simple and inexpensive measurement system that utilizes the non-destructive and contactless free space method is used Dependencies of the reflection and transmission coefficients on water-to-cement ratio, prepaying and curing conditions of the specimens are demonstrated It is shown that the reflection coefficient is approximately stable after hydration process while the transmission coefficient changes during long time of the specimen Is service live. The complex dielectric permittivity of the cement-based materials is calculated by a new method using only the amplitudes of the reflection and transmission coefficients. The expected applications of the results are discussed

Measurement and monitoring of microwave reflection and transmission properties of cement-based materials for propagation modeling

In this paper a non-destructive, contactless free-space method is used for measurement and monitoring of cement-based materials' properties. The propagation factor, penetration depth and reflection and transmission coefficients of the plane wave, interacting with the high lossy specimen, is analysed. Results of the measurement and monitoring of cement-based materials properties during all stages of their lives and different curing conditions are presented. The expected applications of the results for propagation modelling are discussed