Experimental study on the electrical properties of cement composites with carbon nanotubes for monitoring the stress conditions of reinforced concrete structures

Cement composites reinforced with Multi-Walled carbon NanoTubes (MWNTs) are smart materials since the electrical resistivity changes by varying the stress conditions. In this paper data on pressure-sensitive behavior under compressive stress of cement pastes and mortars containing different percentages (from 0.1% to 1.5% vs cement mass) of MWNTs are presented. In order to form a conductive network and enhance the piezoresistive properties of cementitious mixtures, Carbon NanoTubes (CNTs) were efficiently dispersed in the cement matrix by a surfactant (LAS) in an aqueous solution. At the end of the mixing procedure, a defoamer (tributyl phosphate) was added in order to decrease the air bubble in MWNT filled cement-based composites created by the surfactant. Experimental results show that the electrochemical impedance changes synchronously with the compressive stress levels for all the specimens. Moreover, the piezoresistive response is better for cement mortar and increases adding more CNTs percentage.