SBIR Phase I: Passive Sensor for Lifetime Monitoring of Concrete

This Small Business innovation Research Phase I project proposes to demonstrate the feasibility of using a passive sensor, embedded within concrete, to measure moisture, temperature, and concentrations of chlorides. It will 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. Data obtained from these sensors should result in longer service life, lower infrastructure costs and the development of more effective means of remediation. The device will be powered and interrogated using radio frequency energy from a distance of over one meter, returning a unique identification number so that data can be correlated with sensor location. Data will be read by frequency analysis of one or more RLC antennas in the device, whose resonance frequencies will be altered by changes in the surrounding material. The initial strength and the service life of concrete used in roadways and its moisture content from the time that it is placed onwards significantly affects bridges. Such a multi-functional 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.