Cement Based Strain Sensor: A Step to Smart Concrete

In this study cement based sensor (CBS) which will be used as strain sensors was investigated. Eleven mixes having steel fibers of different lengths and volume fractions were designed. Electrical resistance measurements with and without compressive load were conducted. The correlations between the electrical resistance change and strain were determined. The performance measures of gage factor, linearity and strain limit were determined. The gage factor (fractional change in electrical resistance per unit strain) of commercial metal strain gages is around 2 while much higher gage factors as high as 30 is obtained from CBS. The CBS is much more sensitive in strain sensing with respect to commercial metal strain gages. The CBS will be placed in the concrete member and act like an aggregate while working as a strain sensor. The development of CBS will be an important step for use of smart materials in the construction industry.