Mechanical properties and self-healing capacity of eco-friendly ultra-high ductile fiber-reinforced slag-based composites

This paper presents an experimental investigation of the mechanical properties and an evaluation of the self-healing properties of eco-friendly ultra-high ductile fiber-reinforced alkali-activated slag (AAS)-based composites. Based on single types of activators, optimal mixtures were designed and prepared. Compressive strength and uniaxial tension tests were performed to measure the mechanical properties of each composite mixture. In addition, a series of experiments, including self-healing observation by microscopy and stiffness recovery measured through resonant frequency, was undertaken to evaluate the self-healing capacity of alkali-activated slag-based composites. SEM/EDS analysis was utilized to visualize the healing morphology and chemical compositions of the healing materials. The test results showed that AAS-based composites achieved excellent tensile ductility, accompanied with reasonable self-healing performance. Moreover, calcium carbonate was found to be the main healing material in the case of calcium activator-based AAS composites, whereas C-(N)-A-S-H was the dominant healing product generated for sodium activator-based AAS composites. The new findings provide inspiration for an eco-friendly construction material capable of sustainability in terms of material greenness, impressive tensile behavior, and high potential self-healing property.