RAAC panels can suddenly collapse before any warning of corrosion-induced surface cracking

Area of Science:

• Civil Engineering
• Materials Science
• Structural Integrity

Background:

• Reinforced autoclaved aerated concrete (RAAC) panel collapse is a growing concern.
• Experimental data on RAAC corrosion is limited, necessitating computational approaches.
• Existing models inadequately represent concrete porosity's role in corrosion-induced cracking.

Purpose of the Study:

• To computationally model concealed corrosion in RAAC panels.
• To investigate the influence of high porosity on corrosion concealment.
• To identify conditions leading to sudden RAAC panel failure.

Main Methods:

• Developed an enriched corrosion-induced cracking model.
• Incorporated analytical solutions for reactive transport equations (rust precipitation).
• Included a porosity-dependent description of diffusivity.

Main Results:

• First computational study of corrosion concealment in RAAC panels.
• Demonstrated that RAAC panels can collapse suddenly without prior surface cracking.
• Mapped conditions conducive to sudden collapse.

Conclusions:

• High porosity in RAAC significantly impacts corrosion concealment.
• Sudden collapse of RAAC panels is possible before visible signs of corrosion.
• The developed model provides insights into RAAC structural safety under corrosion.