Coupling effect assessment of vacuum based pozzolana slurry encrusted recycled aggregate and basalt fiber on mechanical performance of fiber reinforced concrete

To deal with the rapidly increasing construction and demolition (C&D) waste, the use of eco-friendly and resource efficient concrete in structural applications has become greatly essential for the modern-day construction industry that emphasizes on green environment and sustainability. In this regard, the applications of recycled concrete aggregate (RCA) in place of virgin aggregate can be of great profitable use however, its inferior quality and lower mechanical properties are the major challenges which limit their practical adaptation. To augment the mechanical performance of RAC and promote its structural applications, we applied a new eco-friendly and effective strength-enhancing technique that involves synergistic use of vacuum-based encrusted RCA and fiber reinforcing technique. The performance of this new technique is assessed for two types of RAC containing 20% and 100% of pozzolana slurry treated RCA and reinforced with 0%, 0.25%, 0.5%, and 1% volume fractions of basalt fiber (BF) with regards to various physical and mechanical properties. The compressive loading capacity, splitting tensile strength and flexural strength of BF reinforced 20TRAC formulation reveal maximum improvement of 16%, 24% and 57%, respectively, while that of BF reinforced 100TRAC formulation show maximum enhancement of 8%, 18% and 37%, respectively. Furthermore, the microstructure study revealed improved concrete matrix quality and excellent bonding between BF and host concrete matrix. The ultrasonic pulse velocity and water absorption increased with increase in the BF dosage. Lastly, the correlation analysis for various physical and mechanical properties is presented that depicts an excellent relationship with a correlation factor of greater than 0.9. Conclusively, the composite addition of vacuum-based pozzolana slurry treated RCA and BF constitutes better microstructure and thereby is able to upgrade the mechanical performance of fiber reinforced recycled concrete.