To investigate residual properties of Ultra-High Performance Concrete (UHPC) containing steel-polypropylene hybrid fiber subjected to fire accidents during construction, uniaxial compressive tests were carried out on UHPC exposed to elevated temperature at early age. The test parameters include the age exposed to elevated temperature, temperature levels, steel fiber content and coarse aggregate content. Based on the test results, failure mode, strength, elastic modulus, peak strain, and strain-stress response of the tested specimens were analyzed. Additionally, microstructures of the specimens were characterized using X-ray diffraction and scanning electron microscopy. The test results show that up to 600 °C, the residual compressive strength of the UHPC generally increases with age due to the improved resistance and accelerated hydration. At 800 °C, the strength decreases slightly with age due to the porosity and carbonation reactions. Finally, an empirical formula was proposed to predict the compressive strength, peak strain, elastic modulus, and the uniaxial compressive stress-strain constitutive model of the UHPC exposed to elevated temperature at early age.
Export Date: 18 December 2024
Correspondence Address: Yu, M.; School of Civil Engineering, China; email: ceyumin@whu.edu.cn
Funding details: National Natural Science Foundation of China, NSFC, 52178157
Funding details: National Natural Science Foundation of China, NSFC
Funding text 1: This study was supported financially by the National Natural Science Foundation of China (Grant NO.52178157).