Investigation on Self-Sensing Capability of Different Grades of Carbon Black in Cementitious Composites

Nowadays, the sensors are embedded or mounted on the surface of civil infrastructures for their structural health monitoring. In the present investigation, the self-sensing capabilities of cement composites are studied using different grades of carbon black (CB) in different ratios based on their piezo-resistive behavior. Three grades of CB were studied including one hard type (N330) and two soft types (N550 and N660). Initially, different mixes were prepared with CB filler percentage up to 15% replacement of cement for each type of CB. Cubes of 50 mm × 50 mm × 50 mm were prepared and reversible loading was applied to the specimens. The results showed that a reversible piezo-resistive behavior is shown by composites having higher percentages of CB. Among CB grades, N330 depicted the highest value of compressive strength as well as the best piezo-resistivity. The statistical analysis using the ANOVA test reported that the addition of CB ameliorated the compressive strength results of concrete efficiently. Based on the study, it can be suggested that the CB-based cement composites can be employed for the monitoring of strains in civil engineering infrastructures without reducing the compressive strength of concrete.