Development of a wireless stress/strain measurement system integrated with pressure-sensitive nickel powder-filled cement-based sensors

A wireless stress/strain measurement system is developed by integrating with pressure-sensitive sensors for health monitoring of concrete structures. The pressure-sensitive stress/strain sensors are fabricated by using nickel powder-filled cement-based composite. The wireless stress/strain measurement system integrated with these sensors is tested with compressive stress/strain in the range from 0 MPa/0 μ to 2.5 MPa/311.5 μ for performance evaluation. Experimental results indicate that the electrical resistivity of pressure-sensitive nickel powder-filled cement-based stress/strain sensors changes linearly and reversibly with the compressive stress/strain, and its fractional change goes up to 42.719% under uniaxial compression. The relationship between input (compressive stress/strain) and output (the fractional change in electrical resistivity) of the wireless stress/strain measurement system integrated with pressure-sensitive sensors is Δρ = −0.16894σ/Δρ = −1336.5. The wireless stress/strain measurement system can be used to achieve a sensitivity to stress/strain of 16.894% MPa⁻¹/0.13365%μ⁻¹ (a gauge factor of 1336.5) and a stress/strain resolution of 150 Pa/0.02 μ. The newly developed wireless stress/strain measurement system integrated with pressure-sensitive nickel powder-filled cement-based sensors has such advantages as high sensitivity to stress/strain, high stress/strain resolution, simple circuit and low energy consumption.