Work

Influence of post-fire recuring regimes on the properties of self-compacting concrete with heavyweight aggregate

Year: 2025

Type: article

Abstract: Fire safety is essential in construction, as accidental fires subject concrete structures to high temperatures that result in significant damage. This study examines the development of self-compacting concrete (SCC) characteristics with barite heavyweight aggregate (20–100% substitution of natural coarse aggregate) after being exposed to 600 °C, followed by several post-fire re-curing methods (water, CO 2 , water-glass, and air). The property evolution was examined for cracking, density loss, residual compressive strength, and ultrasonic behavior, verified by FTIR, MIP, and SEM–EDX tests. The exposure to 600 °C resulted in widespread microcracking, significant mass loss, and decreased strength, besides the severity increasing with higher barite concentrations due to the brittleness and thermal sensitivity of heavyweight aggregate. Post-fire curing demonstrated specific recovery mechanisms: water curing promoted rehydration and achieved partial strength recovery of approximately 75% of pre-fire values; CO 2 curing improved densification via carbonation but resulted in increased brittleness; water-glass curing partially filled cracks but decreased long-term stability; and air curing caused additional drying shrinkage and further deterioration. The results highlight the interrelated chemical and microstructural changes that influence the post-fire development of SCC characteristics, revealing that water and CO 2 re-curing are the most effective methods for performance restoration.

Source: Scientific Reports

DOI: 10.1038/s41598-025-19737-6