沥青混合料低温抗裂性能试验方法研究进展

Research Progress on Test Methods of Asphalt Mixture’s Low-temperature Anti-cracking Performance

在寒冷和温差较大的地区,低温开裂是沥青路面病害的主要破坏形式。裂缝的产生影响了路面的完整性、连续性及美观,会导致水通过裂缝渗入路面结构,进而削弱了沥青与骨料之间的粘附力,易诱发其他病害,严重缩短了沥青路面的使用寿命。为评价沥青混合料低温抗裂性能,广大科技工作者探索了多种室内试验和评价方法。但由于沥青混合料是一种多相、多组分、多尺度的黏弹性材料,受力极其复杂。因此不同试验方法的试件尺寸、形状、试验温度、加载速率等对混合料的受力状态影响显著,试验结果存在较大的差异性,导致评价指标和评价标准也各有差异,未形成统一标准,故目前仍没有一种简单有效且公认的方法。目前,根据沥青路面开裂的相关判据及理论基础将现有试验分为:连续体试验、断裂力学试验和声发射试验。连续体试验试件完整、无需再处理,评价多为力学指标;断裂力学试验评价多为能量指标,评价更全面;声发射试验为无损检测技术,可结合宏观试验进行裂缝扩展特性研究。本文结合路面低温开裂的机理,系统归纳了沥青混合料低温抗裂性能试验方法的研究进展,对各种评价方法的优缺点进行评述和对比总结,并结合试验评价难度、试验结果变异性与现场实际受力相关性等方面,探讨了进一步深研的方向,以期为确定科学合理、客观真实、系统全面的沥青混合料低温抗裂性能试验与评价方法提供参考。

For the asphalt pavement, low-temperature cracking is the major damage form in the cold and large temperature variation region. The continuity and aesthetics of the pavement are seriously influenced by the cracks, which make the water through the cracks into the pavement structure. More seriously, the adhesion between asphalt and aggregate is weakened, and reduced the service life. A variety of indoor tests and evaluation methods are given by the researchers. As the asphalt mixture is a multi-phase, multi-component, multiscale relativistic material, with the extremely complex mechanical property. Lots of uncertain factors lead to inconsistent results by different test methods, such as the specimen size, shape, test temperature, loading rate, so the evaluation index and standard for different experiment methods are disunity, so none of them are widely recognized until now. At present, the criteria and basis theoretical for asphalt pavement cracking are mainly continuum test, fracture mechanics test and acoustic emission test. The mechanical indicator for continuum test specimen is complete and direct;more comprehensive is the super features for the fracture mechanics test evaluation by energy indicators;the crack propagation characteristics can be researched by the acoustic emission test and macroscopic test. In this paper, the test methods for low temperature crack resistance of asphalt mixture are systematic review and comparison summary. Based on the difficulty of test evaluation, the variability of test results, and the correlation with the actual stress on site discussed, the future valuable research directions are given. Which helps to get the scientific, reasonable, systematic and comprehensive test and evaluation method for low temperature crack resistance of asphalt mixture.