Sensing Performance of Engineered Cementitious Composites in Different Application Forms

The method of application of self-sensing composites in structural health monitoring is urgent to be determined before real application. In this paper, the mechanical and sensing properties of self-sensing engineered cemen-titious composites (ECC) under monotonic and variable amplitude cyclic tension and compression were analyzed. With the consideration of different application forms such as sensor, coating and bulk types, three kinds of concrete samples were prepared. For each sample, the sensing properties and applicability of piezoresistive effect were analyzed and compared. The results demonstrate that the developed self-sensing ECC guarantees desirable sensing performances and high ductility with a tensile strain of above 6.0%. The gauge factor (GF), signal-to-noise ratio (SNR) and repeatability are 165.48, 53.07 and 4.19%, respectively in compression, while they are 14.71, 25.05 and 7.16%, respectively in tension. It was verified that the sample strain could be constantly monitored by self-sensing ECC, especially when the strain is less than 0.005 %. Compared with coating and bulk types, the sensor type could significantly improve the sensitivity, SNR and repeatability. Besides, the sensor type could eliminate the zero drift greatly and has little negative effect on the mechanical properties of samples.