Synthesis and characterization of self-healing geopolymer composite

This paper introduces a novel, green, self-healing composite based on vascular luffa fibres (Luffa Cylindrical Fibres, LCF) and a geopolymer matrix. The self-healing effect of LC fibre in reinforced geopolymer was investigated. For comparison purposes, other two geopolymer composites, GC4 and GJ4, were prepared using synthetic carbon fibre and natural jute fibre, respectively, as reinforcements. To evaluate these geopolymer composites, their pre- and post-cracking mechanical properties were tested on 100 mm × 20 mm × 5 mm rectangular specimens, cracked by means of three-point bending. The specimens were initially cracked to approximately 0.5 mm and were then exposed to the ambient conditions for 30 days. During this treatment period, the specimens were wetted with water every three days. Results show that the cracks were healed only in the LC fibre reinforced geopolymer composite, and closed by non-soluble mineral phases as a result of up-taking CO₂ from air. The composite restored part of its original mechanical performance over the 30 days of ambient exposure conditions.