超低温作用下UHPC受弯力学行为及其本构关系

Flexural Behaviour and Constitutive Correlation of UHPC at Cryogenic Temperatures

研究了不同温度下超高性能混凝土(UHPC)的受弯力学行为,并利用吸能效率、声发射能量释放率和振铃计数表征了UHPC脆性失效的演变机制,构建了3种UHPC受弯本构模型.结果表明:当温度为-170℃时,UHPC的初裂抗弯强度和峰值抗弯强度分别从20℃的10.6、20.9 MPa增至21.1、42.5 MPa;在20~-170℃范围内,UHPC的脆性随温度降低先减小后增大,并在-80℃时达到最小值、-170℃时达到最大值;相较于过镇海教授和吴泽媚博士的本构模型,线性-非线性本构模型的预测精度最高、数据离散性最低.

The flexural mechanical behavior of ultra⁃high performance concrete(UHPC)at different temperatures was studied.The brittle failure evolution mechanism of UHPC was characterized with energy absorption efficiency,acoustic emission energy release rate and ring⁃down count.Three flexural constitutive models of UHPC were established.The results show that when the temperaure is-170℃,the first⁃peak and maximum flexural strength of UHPC increase from 10.6,20.9 MPa at 20℃to 21.1,42.5 MPa,respectively.Within the range of 20--170℃,with the decrease of temperature,the brittleness of UHPC firstly increases and then decreases,showing the minimum brittleness at-80℃and the maximum brittleness at-170℃,respectively.Compared to the constitutive models of Prof.Guo Zhenhai and Dr.Wu Zemei,the linear⁃nonlinear constitutive model has the highest prediction accuracy and the lowest data variability.