C60低收缩低徐变高性能混凝土收缩徐变行为试验研究

Experimental study on shrinkage and creep behavior of C60 low shrinkage and low creep high performance concrete

为探究C60低收缩低徐变高性能混凝土不同加载龄期和应力水平下的收缩徐变机理,开展了常规环境下不同加载龄期和应力水平的C60低收缩低徐变高性能混凝土收缩徐变试验研究,对实测结果与常用规范模型结果进行对比分析。结果表明:在常规环境下,C60低收缩低徐变高性能混凝土加载龄期为7、24 d持荷270 d的线性徐变系数分别为0.80和0.38左右,是C60普通混凝土的0.4~0.6倍;收缩应变和徐变系数实测值相比GL2000、ACI-209、JTG 3362—2018和AASHTO规范模型计算值均偏小,偏差达40%。根据实测试验结果,在线性徐变范围内,引入收缩修正系数对JTG 3362—2018模型进行修正,分别建立常规环境下C60低收缩低徐变高性能混凝土收缩应变和线性徐变系数预测模型,计算结果与试验结果误差较小,可为指导实际工程的应用提供依据。

In order to explore the shrinkage and creep mechanism of C60 low-shrinkage and low-creep high-performance concrete under different loading ages and stress levels,the shrinkage and creep of C60 low-shrinkage,low-creep high-performance concrete under different loading ages and stress levels under conventional environments were developed.Experimental research,comparative analysis of the measured results and the results of commonly used standard models.The results show that under normal conditions,the linear creep coefficients of C60 low-shrinkage and low-creep high-performance concrete with a loading age of 7 d and 24 d and a load of 270 d are about 0.80 and 0.38,respectively,which are 0.4~0.6 times that of C60 ordinary concrete.Compared with the calculated values of GL2000,ACI-209,JTG 3362—2018 and AASHTO standard models,the measured values of strain and creep coefficients are all smaller,with a deviation of 40%.According to the measured test results,within the linear creep range,the JTG 3362—2018 model was modified by introducing a shrinkage correction coefficient,and the shrinkage strain and linear creep coefficient models of C60 low-shrinkage and low-creep high-performance concrete under conventional environments were established respectively.The calculation results is in good agreement with the test results and can provide a basis for guiding the application of actual projects.