The initial strength and the service life of concrete used in roadways and bridges is significantly affected by its moisture content from the time that it is placed onwards. A sensor that could detect moisture, temperature, pH, and the concentration of chloride, sodium and potassium ions would provide critical data for evaluating concrete performance starting with the initial quality control period of freshly mixed or freshly cast concrete, through its useful service life, to the period of deterioration and repair. Such a multifunctional sensor can be so pervasively useful because moisture and temperature are the primary drivers for the hydration of portland cement, and are essential factors in the most prevalent deteriorative processes such as damage due to freezing and thawing, alkali-aggregate reaction, sulfate attack or delayed Ettringite formation.
ADC combines radio frequency identification devices, or RFIDs, with its MEMS sensors in a package that can mix with Portland cement. Many of these new devices can be embedded in a new bridge, building or roadway. The ultra-small sensor monitors moisture, temperature, pH, as well as the concentration of chloride, sodium and potassium ions within the concrete. These devices will provide critical data for evaluating concrete performance from its freshly mixed stage to its casting, through the concrete's service life, to its period of deterioration and repair.
MEMS Concrete Monitoring System