A self-sensing and self-heating planar braided composite for smart civil infrastructures reinforcement

Allocating different capabilities to structural elements simultaneously is still challenging. In this study, a field-applicable multifunctional planar braided composite with the abilities of reinforcing, self-sensing and self-heating was developed for the first time. In this route, three commercial fabrics were used, including cotton, cotton/polyamide, and polyester. The fabrics were first chemically treated and then coated with a carbon nanomaterial-based polymeric conductive paste using screen printing with different concentrations and layers. The samples were then covered and sealed with a thermoplastic polyurethane-based polymer to avoid environmental factors effects. Smart planar composites (SPC) were also used as reinforcement for cementitious specimens. The electrical conductivity and joule heating capability of the samples were also evaluated. The microstructure of the SPCs was investigated using various tests. The mechanical and self-sensing performances of the cementitious composite reinforced with different SPCs were assessed using different load patterns. The results showed a heating rate of 0.44 ˚C/s, a joule heating power of 0.7 W/˚C, and a maximum temperature of 44 ˚C which proved the proper heating capability of the cementitious composites reinforced with SPCs. The great correlation between electrical resistivity changes and strain values indicated the high potential of the composite in strain sensing for different applications. The SPCs also improved the post-crack behaviour of the specimen and its flexural strength and failure strain by approximately 50% and 118%, respectively. The outcomes of this study draw a bright horizon in multifunctional braided composite development with different applications in civil infrastructures, which is a crucial step for intelligent cities' advances.