Temperature influence on electromagnetic measurements of concrete moisture

Abstract

In order that non-destructive testing methods become quantitative tools for structure owners, it is necessary to assess their precision and sensitivity to the environment. The presented study deals with two electromagnetic methods classically used to survey road pavements and concrete structures: a radar technique and a capacitive technique. The presented investigations aim at assessing the influence of temperature and moisture on the two methods for measurements realised on concrete slabs. The temperature was ranging from 5 to 45°C and the surrounding relative humidity (RH) evolved between 60 and 90%. The study is part of a more ambitious topic aiming at defining quantitative non-destructive methods to evaluate the water content of concrete structures on site and their state of degradation. The presented work allows assessing the sensitivity of both radar and capacitive techniques to the environmental conditions: temperature and RH. Moreover, the measurement variability of the used capacitive probes with three different sets of electrodes is estimated.

Evaluation of chloride contamination in concrete using electromagnetic non-destructive testing methods

“…This technique, and the corresponding sensor, was designed by the network of laboratories of the Ministry of Ecology, Sustainable Development and Energy (France) and tested in reinforced concrete structures [16][17][18]. The principle of the capacitive technique is to measure the resonance frequency of an oscillating circuit (around 30-35…”

“…The technique tested in this study used a four-probe square device that injects electrical current between two lateral probes and measures the potential difference between the other two probes [18][19][20]. The apparent resistivity is deduced from the ratio of the potential to the intensity, according to the geometrical characteristics.…”

Temperature Effect on Electrical Resistivity Measurement Using an Embedded Sensor to Estimate Concrete Water Content

“…Sci. 2022, 12, 9420 2 of 12 concrete influences the concentration and mobility of the ions and the ion-ion and ionsolid interactions [20]; therefore, it affects the measured resistivity [21,22], as well the electromagnetic permittivity [23]. These interactions can be different for cements of different chemical composition (e.g., slag or fly ash).…”