Assessing self-healing in high-performance concrete with superabsorbent polymers by an innovative methodology

Abstract

This study introduces a novel cracking methodology used in high-strength concrete (HSC) with superabsorbent polymers (SAP) to unveil its actual self-healing potential without fibre reinforcement. Although high-strength concrete allows for more creative structural designs and reduces the amount of building materials used, it often suffers from self-desiccation, which can cause cracking issues. SAP's inclusion in HSC not only addresses the autogenous shrinkage problem but also enhances concrete's self-healing capabilities. This research focuses on the dual role of SAP in mitigating autogenous shrinkage and promoting self-healing in high-strength concrete. An innovative technique was employed to induce uniform, controlled cracks under direct tension by isolating the self-healing agent's effect. The cracking process was developed using nonlinear finite element analysis. Two SAP concentrations (0.3 % and 0.6 %) were tested on specimens with a consistent crack width of 200 µm. These specimens underwent daily wetting-drying cycles over four months, with evaluations at 7 and 28 days post-cracking. Self-healing effectiveness was measured through mechanical recovery and microscopic examination of crack closure. Results, as expected, revealed a modest healing level but showed the actual potential of self-healing that this kind of concrete (HSC) can be counted on, offering crucial insights into self-healing concrete's practical applications and limitations. This study demonstrates SAP's versatility and highlights another advantage of SAP in high-strength concrete. This advantage, while slight, encourages the use of SAP in concrete and advances the creation of more durable construction materials.