Self-sensing behavior of carbon fiber reinforced lightweight cementitious composites under simultaneous conditions of mechanical loading and environmental effects

Cement-based materials can be endowed with piezo-resistive behavior having a huge potential to provide continuous structural health monitoring for several civil engineering applications. Although piezo-resistivity of cement-based materials have been addressed for a few decades under mechanical loading and ambient conditions, a better understanding of the simultaneously occurring effect of different environmental conditions can largely foster their widespread transfer into practice. The current investigation undertakes the self-sensing ability of lightweight cementitious composites under mechanical loading superimposed with different environmental conditions such as temperature, moisture and freeze/thaw cycles. The lightweight cementitious composites were designed pre-targeted having a compressive strength of at least 16 MPa and a density of 1300 kg/m3 to be compatible with the prescriptive of lightweight structural design where self-sensing is of interest in structural/ non-structural applications. Our results revealed that the effect of moisture favors the self-sensing behavior without mechanical loading, however, piezo-resistivity was adversely affected during mechanical loading. The self-sensing ability of the specimens under elevated temperature was similar with and without mechanical loading and were highly responsive compared to specimens at ambient conditions. On the other hand, the electrical resistivity of cyclic frost action was continuously monitored, and specimens were responsive to changes of strain due to viscosity of water and the change of water-saturation conditions.