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

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振动与冲击 ›› 2024, Vol. 43 ›› Issue (9) : 214-225.

论文

赵东拂1,2,3,4,5，李浩1，郝腾飞1，刘梅1

作者信息 +

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

Author information +

文章历史 +

摘要

对经历不同加热温度和恒温时间的C60高强混凝土试块进行试验研究，以分析其细微观结构演变机理，建立高强混凝土高温历程与细微观结构演化关系模型和高温历程与剩余强度关系模型。通过热电偶测得试块内部温度场，并结合ABAQUS有限元模拟分析试块内部温度场分布规律，结果表明两者试块内部温度场变化基本一致；利用扫描电子显微镜、X射线衍射、显微硬度检测、汞压力测孔、超声五种测试手段，对不同高温历程后高强混凝土材料的细微观结构变化进行定性和定量分析，并且彼此印证，建立了高强混凝土高温历程与细微观结构演化关系模型；通过测强试验获得高温后高强混凝土剩余抗压强度，建立了高强混凝土高温历程与剩余强度关系模型。研究表明：随着温度升高，恒温时间增长，结晶水散失，水化产物、凝胶有不同程度分解，氢氧化钙、白云石、钙矾石含量减少，声时增加，波幅、频率减小，显微硬度下降，孔隙率上升。最终得出了高强混凝土材料高温历程、细微观结构及剩余强度之间的关系。

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.

导出引用

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[J]. Journal of Vibration and Shock, 2024, 43(9): 214-225

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