沥青混合料玻璃态转变温度的外部影响因素

为探究环境因素、交通水平等外部条件对沥青混合料玻璃态转变温度的影响,研究选取升温速率、荷载频率、应变水平3个试验因素,采用DMA方法在不同试验水平下对沥青混合料试件进行温度扫描试验.利用Boltzmann模型拟合得到材料的玻璃态转变温度,通过对试验结果的统计分析,确定影响玻璃态转变温度的主要因素,并建立了多因素影响下的玻璃态转变温度预测模型.结果表明:采用Boltzmann模型能够准确有效地确定材料玻璃态转变温度;升温速率、荷载频率对沥青混合料的玻璃态转变温度有显著影响,玻璃态转变温度随着升温速率、荷载频率的增大而升高,玻璃态转变温度与升温速率、荷载频率的对数值存在良好的线性关系;处于弯拉受力模式下的沥青混合料,其玻璃态转变温度在线粘弹性区域内并无明显的应变依赖性.

External influence factors on the glass transition temperature of asphalt mixture

In order to explore the influence of external conditions on the glass transition temperature of asphalt mixture, such as environment and traffic, three factors including heating rate, load frequency, and strain level were considered in this research. Temperature sweep test was developed by DMA method at different test levels. The glass transition temperature of asphalt mixture was obtained by Boltzmann model. The main affecting factors of glass transition temperature were determined by statistical analysis of the experimental results, and then the prediction model of the glass transition temperature under multiple factors was established. Results show that the Boltzmann model could accurately and effectively determine the glass transition temperature of asphalt mixture. The heating rate and load frequency had a significant effect on the glass transition temperature, which increased as the hating rate and load frequency increased. In addition, there was a good linear relationship between the glass transition temperature and the logarithm of heating rate and the load frequency. The glass transition temperature of asphalt mixture had no obvious strain dependence in liner viscoelastic region under bending mechanics condition.