Study of the temperature-induced degradation in the fracture behaviour of polyolefin fibre-reinforced self-compacting concrete

Concrete stands as the most widely used construction material in the last decades. At the same time, the use of macro-polymer fibres has gained interest due to their notable benefits. Although concrete exhibits meritorious structural behaviour, it is imperative to acknowledge that when fibre-reinforced concrete is exposed to certain phenomena such as high temperatures, it faces significant risk. While there is a vast scientific literature that addresses this issue, most of it does not reflect the behaviour of the material at the precise moment when it is subjected to high temperatures. With this target, this research has focused on analysing its flexural response at 20, 165, 185, and 200°C. To carry out this study, it was required to carefully isolate the specimens, thus minimizing temperature loss during testing. Once the tests were completed and detailed analysis of the fracture surfaces was performed, the results obtained indicated that polyolefin fibres reduce the risk of spalling, and that as the temperature increases, the residual load-bearing capacity of the material is affected until it reaches a similarity to the behaviour of plain concrete at the maximum temperature studied. • High temperatures limit the performance of polyolefin fiber-reinforced concrete. • Flexural test, following EN 14651, were conducted at 20, 165, 185, and 200°C • At 165°C, fibre-reinforced concrete shows initial strength reduction. • At 185°C, the material's residual load-bearing capacity declines further. • At 200°C, concrete behaves similarly to plain concrete.