利用改进开窗转换法确定沥青离散松弛时间谱

为了精确地获得沥青胶结料的离散松弛时间谱,提出了一种改进开窗转换法的线性黏弹性材料函数转换算法．此方法可以用于离散延迟时间谱和离散松弛时间谱的相互转换．与开窗转换法相比,改进开窗转换法对于时间常数的设置更加精确,并且不会产生负数谱线．将改进开窗转换法用于一种传统非改性沥青的弯曲梁流变仪试验数据的离散延迟时间谱的转换,成功地确定了相应的离散松弛时间谱．经有限元模型验证表明,此离散松弛时间谱能很好地还原该沥青结合料的应力松弛特性．

Determination of discrete relaxation time spectra of asphalt utilizing improved windowing interconversion method

To accurately obtain discrete relaxation time spectra of asphalt binders, an algorithm termed the improved windowing interconversion method (IWIM) is presented in this paper. The IWIM allows discrete retardation time spectra to be converted into discrete relaxation time spectra, and vice versa. Compared with the windowing interconversion method (WIM), the IWIM affords a more exact distribution of time constants without generating negative spectrum lines. The IWIM was applied to the discrete retardation time spectrum of bending beam rheometer (BBR) test data for a conventional unmodified asphalt binder, successfully determining the discrete relaxation time spectrum. The result of the validation by means of a BBR test finite element simulation shows that the discrete relaxation time spectrum from the IWIM can well reproduce the stress relaxation properties of the asphalt binder.