Post-fire compressive stress-strain behaviour of steel fibre reinforced recycled aggregate concrete

The uniaxial compressive tests were carried out to investigate the post-fire compressive stress-strain behaviour of steel fibre reinforced recycled aggregate concrete (SFR-RAC) after being exposed to elevated temperatures. The test parameters include water-to-cement ratio, recycled concrete aggregate (RCA) substituting ratio, steel fibre content and heated temperature. The failure mode, strength, elastic modulus, peak strain, and strain-stress response of the tested specimens are analysed. The test results show that the compressive strength and elastic modulus decreased with the increase of water-to-cement ratio and/or RCA substituting ratio at any exposed temperature. The residual strength retained about 83%, 85%, 56% and 23% of their ambient compressive strength on average after being exposed to 200, 400, 600 and 800 degrees C, respectively. The steel fibre has a positive effect on the residual mechanical properties and its effect increases with the increase of heated temperature. Based on the test data, a simplified explicit formula was proposed for predicting the compressive strength, peak strain, elastic modulus, and uniaxial compressive stress-strain constitutive model of the SFR-RAC.

Automated summary

The post-fire compressive stress-strain behavior of steel fiber reinforced recycled aggregate concrete (SFR-RAC) after exposure to elevated temperatures was investigated through uniaxial compressive tests. The test considered parameters such as water-to-cement ratio, recycled concrete aggregate (RCA) substituting ratio, steel fiber content, and heated temperature. The study analyzed the failure mode, strength, elastic modulus, peak strain, and strain-stress response of the specimens. The results showed that the compressive strength and elastic modulus decreased with increased water-to-cement ratio and/or RCA substituting ratio at any exposed temperature. The steel fiber had a positive effect on the residual mechanical properties, which increased with the heated temperature.