Effect of nanocarbon black structure on self-strain-sensing performance of cementitious composites

The utilization of nanocarbon black (nCB) in cementitious composites has shown significant potential for developing self-sensing concrete with intrinsic strain monitoring and damage detection capability. While nCB with different morphologies and surface areas have been used to produce self-sensing concrete, there is a considerable knowledge gap in understanding how the structure of nCB influences the performance of these smart materials. In this study, the effect of nCB structure on the mechanical and piezoresistive properties of nCB-based self-sensing concrete is investigated. The investigation concludes that the compressive strengths of all the nCB-based composites, regardless of nCB structure, show similar trends: as nCB dosage increases, strength initially increases compared to plain concrete, and then decreases. On the other hand, the composite with high-structure nCB, which has a branched morphology, possesses a very low and distinct percolation zone, beneficial to realizing large-scale implementation due to cost-efficiency. Moreover, it exhibits the highest strain sensitivity as well as highly repeatable and precisely synchronized response to the applied compressive stress-strain. The outcomes of this study shall contribute to the foundational knowledge base for the development of next-generation smart infrastructure, enabling real-time structural health monitoring to enhance safety and service life.