Autonomous Repair in Cementitous Material by Combination of Superabsorbent Polymers and Polypropylene Fibres: A Step Towards Sustainable Infrastructure

TL;DR

This study demonstrates that combining superabsorbent polymers and polypropylene fibers in mortar enables autonomous crack healing, restoring mechanical strength and durability, thus offering a sustainable alternative to traditional repair methods.

Contribution

It introduces a novel combination of SAP and PP fibers that significantly improves self-healing and property recovery in mortar, advancing sustainable infrastructure repair.

Findings

Full mechanical strength recovery after healing.

Durability recovery up to 90%.

Crack sealing ratio of 85% under moist conditions.

Abstract

Manual maintenance and repair of cracks in concrete structures are often unsustainable because of associated labor, capital and environmental damage. Introduction of microfibers and superabsorbent polymers is a material solution to restrict crack propagation and enhance self-healing efficiency. Therefore, the study proposes a combination of polypropylene(PP) fibers and superabsorbent polymers (SAP) which would facilitate autonomous healing and recover original mechanical and durability properties of mortar. Mechanical strength, sorptivity and water penetration of healed mortars were compared to that of undamaged mortar at same age to estimate recovery of original properties while crack sealing was investigated by means of optical microscopy. Experimental results show mortar with combination of PP fibers and SAP showed full recovery of mechanical strength after healing while recovery in durability up to 90% was recorded. Microscopic images show that average crack-sealing ratio of 85% could be achieved under moist condition by combination of SAP and PP fibers while sealing under drier air curing condition is also significantly higher than reference samples with only fibers. Crack width up to 330{\mu}m has been found to be completely sealed by carbonate crystals. Furthermore, mortar with SAP and PP fibers retain about 70% of their original 28-day strength after three cycles of loading while reference mortar samples were found to retain only about 40-50% of their original strength. Effective crack sealing and high recovery of original properties in mortars with SAP and fibers suggest that this material combination would reduce the need for environmentally damaging and expensive repairs during the service life.