Biochar and recycled carbon fibres as additions for low-resistive cement-based composites exposed to accelerated degradation

Biochar (BCH) and recycled carbon fibres (RCF) were used as carbonaceous additions in low-resistive mortars/concretes. Their effects on mechanical, electrical, and durability properties were investigated. Tests were performed both during curing and accelerated degradation. The combined use of RCF and BCH decreased the electrical impedance of cement-based matrices, enabling the use of low-cost monitoring instrumentation, and improved their mechanical performance. Recycled carbon fibres and biochar additions increased carbonation and capillary water absorption but acting as a barrier they made water and chlorides penetrate less deeply.