不同养护温度下高强混凝土早龄期拉伸徐变的试验研究

Experimental Study on Early Age Tensile Creep of High Strength Concrete under Different Curing Temperatures

关键词:  养护温度  高强混凝土  拉伸徐变  早龄期  加载龄期

Key words:  curing temperature  high strength concrete  tensile creep  early age  loading age

摘要:

以C60高强混凝土为研究对象，试验研究了养护温度和加载龄期这2个参数对高强混凝土早龄期拉伸徐变特性的影响.结果表明：随着加载龄期的增长，高强混凝土拉伸比徐变、徐变系数和徐变速度均呈指数衰减的趋势；随着持荷时间的延长，不同加载龄期的高强混凝土徐变速度差异越来越小，且在不同养护温度下均表现出同样的趋势；与养护温度对成熟龄期混凝土拉伸徐变的影响不同，在相同加载龄期下，高强混凝土早龄期拉伸比徐变随着养护温度的升高而降低，但是随着加载龄期的增长，其降低幅度减小，至加载龄期为7000d时各养护温度下高强混凝土的拉伸比徐变基本持平.无论持荷时间是7，14d还是21d，在持荷时间相同时，不同加载龄期高强混凝土之间的拉伸比徐变差异随着养护温度的提高而减小.

Abstract:

The influences of curing temperature and loading age on the early age tensile creep characteristics of C60 high strength concrete were experimentally investigated. The results indicate that the creep speed, creep coefficient and specific creep show an exponential decay with the increase of loading age, and the differences of tensile creep speed at different loading ages become less when the holding time increases. The same tendencies of tensile creep speed and specific creep can be observed under different curing temperatures. It is also showed that the early age tensile specific creep decreases with the increase of temperature at the same loading age. This phenomenon is different from the effect of temperature on the tensile creep of mature concrete. But the decrease magnitude reduces with increasing loading age, and it tends to be essentially flat at loading age of 7000d. The differences of high strength concrete creep between the different loading ages decrease with the increase of curing temperature at the same holding time whenever the holding time is 7, 14d or 21d.