Assessment of concrete sensitivity to fire spalling: A multi-scale experimental approach

Abstract

• Both specimen geometry and fire curve strongly influence spalling evolution. • Differences among tests depend on different evolution of stress and pressure. • Stress appears to play the major role in triggering spalling. • Properly designed small/intermediate-scale tests and full-scale test are consistent. Fire behaviour of R/C structures can be strongly affected by spalling phenomenon, which may offset the positive inherent features of concrete exposed to high temperature. This makes the screening of concretes by testing a key point in the design phase of spalling-sensitive structures. To this aim, three different testing procedures have been adopted within a multi-scale approach for investigating two concrete mixes containing different amounts of fibre. The three typologies of test are discussed by comparing experimental and numerical results, so to cast some light on their main differences. Although the experimental results may appear different, a common key of interpretation is recognized.