Meso-microstructure evolution mechanism and residual strength tests of high-strength concrete after high temperature
ZHAO Dongfu1,2,3,4,5, LI Hao1, HAO Tengfei1, LIU Mei1
1.School of Civil and Transportation Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China；
2.Engineering Structure and New Materials of Beijing University Engineering Research Center, Beijing 100044, China；
3.Beijing Advanced Innovation Center for Future Urban Design, Beijing 100044, China；
4.Multi-Functional Shaking Tables Laboratory, Beijing University of Civil Engineering and Architecture, Beijing 100044, China；
5.Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-construction Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
Abstract：In order to analyze the meso-microstructure evolution mechanism and establish the relationship model between high temperature history and meso-microstructural evolution and the relationship model between high temperature history and residual strength, an experimental study was conducted on C60 high strength concrete specimens experiencing different heating temperature and constant temperature times. The internal temperature field of the specimens was measured by thermocouples and analyzed by finite element simulation analysis of ABAQUS. The result showed that the variation of temperature field in the two tests was basically consistent. The meso-microstructure changes after different high temperature history were analyzed qualitatively and quantitatively by scanning electron microscope (SEM), X-ray diffraction (XRD), microhardness test, mercury intrusion porosimetry (MIP) and ultrasonic, and the results of different means were related to each other. Then the relationship model between high temperature history and microstructural evolution was established. The residual compressive strength after high temperature history was obtained by strength test. Then the relationship model between high temperature history and residual strength was established. The research showed that as the heating temperature and time rose, the water of crystallization is lost, the hydrides and gels have different degrees of decomposition, the calcium hydroxide, dolomite and ettringite decreased, the acoustic time increased, the amplitude and frequency decreased, the microhardness decreased and the porosity increased. Finally, the relationship among high temperature history, meso-microstructure and residual strength of the high-strength concrete was obtained.
赵东拂1,2,3,4,5，李浩1，郝腾飞1，刘梅1. 高温后高强混凝土细微观结构演变机理及剩余强度试验研究[J]. 振动与冲击, 2024, 43(9): 214-225.
ZHAO Dongfu1,2,3,4,5, LI Hao1, HAO Tengfei1, LIU Mei1. Meso-microstructure evolution mechanism and residual strength tests of high-strength concrete after high temperature. JOURNAL OF VIBRATION AND SHOCK, 2024, 43(9): 214-225.
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