Improved anti-corrosion and mechanical aspects of reinforced cementitious composites with bio-inspired strategies

Abstract

The device of self-healing cementitious composites is a most anticipated approach for repair of unavoidable cracks through biological intrusions. The bio-inspired self-healing composites systematically heal the cracks and control the penetration of corrosive ions towards the embedded steel. However, the effect of bacterial additions on the electrochemical performance of embedded steel holds several questions and needed to be explored further. Therefore, this research was carried out to assess the effect of a calcifying bacterial strain “Bacillus safensis” and its carrier media, biochar, on mechanical and transport properties along with the corrosion performance of embedded steel in cementitious composites. The boosted strain energy storing potential with 25.5% and 38.18% enhanced flexural and compressive strength than control sample, respectively was observed. Additionally, about 89% gain in compressive strength was observed after 28 days of cracking at 85% of ultimate compressive strength. Moreover, a significant increase in relative healing degree was seen during ultrasonic pulse velocity measurements of uncracked and cracked samples. Furthermore, the healing precipitate was recognized as calcite through scanning electron microscopy and Fourier transform infrared spectroscopy. The lower sorptivity trends also indicated the denser microstructure with minimum water uptake capability and porosity which lead towards minimum corrosion damage in the embedded steel. Besides, the corrosion inhibition efficiency was noted as 95.18% compared to the control sample. Thus, the proposed combination of biotic and abiotic materials would be a good solution for recycling waste and enhancing mechanical and durability prospects of reinforced cementitious composites.