Realization of Self-Sensing for Coal-Based Solid Waste Cementitious Composites: A Comparative Study of Functional Additive Type

Abstract

Functional additives can be incorporated into coal-based solid waste cementitious composites (CSCC) to create a new self-sensing material that can effectively monitor the health of engineering structures, including those involved in green coal mining. The selection of a functional additive type is critical to realizing the self-sensing performance of CSCC. Based on this, the mechanical and piezoresistive properties of CSCCs incorporated with three functional additives, including carbon fibers (CF), steel fibers (SF), and carbon black (CB), were investigated. The effects of mechanical properties and piezoresistive responses of CSCC during various curing periods were investigated, and the microstructure of the samples was examined using scanning electron microscopy (SEM). The outcomes suggest that adding functional additives may significantly improve the mechanical properties and self-sensing of CSCCs. Due to a well-structured “conductive channel,” the samples with CF produced the biggest fractional change in electric resistance (FCER=33.64%) and the highest gauge factor (K=12.21) under the loading. Furthermore, as the curing period increased, the self-sensing ability of CSCCs with CF deteriorated because of the hydration process consuming free water, as reflected by the largest amplitude of K=62%. The findings can promote the progress of eco-friendly composites and provide a new monitoring idea for ensuring green and safe engineering production.