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 per-formed 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.