摘要 车辙、水损害和抗滑能力衰减是影响防滑磨耗层表面特性的三种主要损坏类型。本文对防滑磨耗层用沥青混合料的高温稳定性、水稳定性和抗滑性能的室内加速试验方法和评价指标作了探讨，初步研究了防滑磨耗层的长期表面特性衰变规律，为建立考虑表面特性的沥青混合料组成设计方法奠定了一定的基础。 抗滑性能方面，针对国内外没有抗滑性能室内加速试验的现状，研制了加速磨耗仪，提出了加速磨耗试验方法。在不同温度下对不同粗集料类型组成的AK-13A混合料作了加速磨耗试验。初步应用表明，该方法可模拟沥青混凝土防滑磨耗层的抗滑阻力衰变机理，用于研究沥青混凝土的抗滑阻力的衰变与材料组成、环境因素等相互关系，并可以用于沥青混合料组成设计。建议使用温度15℃、接地压力0.7Mpa下，磨耗作用130000、200000次后测量的混合料表面构造深度和摆值BPN作为抗滑性能评价指标；高温稳定性方面，对我国常用的防滑磨耗层用沥青混合料类型—SMA-16、AC-161、AK-13A分别作了车辙试验，并对国外单轴蠕变试验和单轴重复加载试验研究成果作了综述。在比较分析三种方法优缺点的基础上，建议以车辙试验作为防滑磨耗层用沥青混合料高温稳定性评价方法。但是，车辙试验的动稳定度指标是一个经验性指标，不能用于沥青路面的结构组成设计。本文提出了基于车辙试验的广义沥青混合料劲度S*mix的概念，弥补了这一不足。动稳定度和S*mix可作为高温稳定性能的评价指标；水稳定性方面，在美国T-283冻融劈裂方法的基础上增加了老化条件和冻融循环次数。对s-16、AC-161、AK-13A分别作的T-283试验和改进T-283试验结果表明，增加老化条件和冻融循环次数对混合料的水稳定性评价有显著影响。建议以改进T-283试验作为防滑磨耗层用沥青混合料水稳定性评价方法，评价指标为中期老化条件和长期老化条件下的残留劈裂强度比TSR。 最后，本文总结了考虑表面特性的沥青混合料设计与评价体系，用于指导防滑磨耗层的材料组成设计。 |
Rutting, moisture damage and reduction of skid resistance are major distress types that impact upon the surface performance of skid-resistant wearing courses．In order to obtain its long-term deterioration equation, the paper developed the laboratory accelerating tests and evaluating index that indicate high temperature stability, moisture stability and skid resistance of wearing course asphalt mixture. Considering there is no laboratory-accelerating test method on skid resistance at present, a kind of accelerating abrasion device was developed and a corresponding test method was provided. At different temperatures, accelerating abrasion tests were performed on AK-13A with different kinds of coarse aggregate. The results indicated this method is feasible. It suggested that the mixture surface texture depth (TD) and BPN measured under the temperature of 15℃，the contact pressure of 0.7MPa and repeated load of 13 000~200 000 times be considered as evaluating indexes. For high temperature stability, rutting test was preformed on the typical skid-resistant asphalt mixtures in China, including SMA-16，AC-161 and Ak-13A. Some research achievement abroad with uniaxial creep test and uniaxial repeated load test were also documented. Comparing their relative merits, rutting test was recommended to evaluate the high temperature stability of skid-resistant asphalt mixture. However, dynamical stability from rutting test is an empirical index, which doesn't meet the structural design of asphalt pavement. The paper Improved it by using the generalized asphalt mixture stiffness (S*mix) based on rutting test. Thus, S*mix can be regarded as an evaluating Index on the high temperature stability. To evaluate moisture stability T-283 freeze thawing split test was modified by adding aging condition and freeze thawing cycles. The results of T-283 and modified T-283 on SMA-16, AC-161, AK-13A indicated that adding aging condition and freeze thawing cycles has a distinct effect on evaluating moisture stability of asphalt mixture. It proposed that modified T 83 be as moisture stability evaluating method of skid-resistant wearing course asphalt mixture. Correspondingly, the evaluating Index of moisture damage is tensile strength ratio (TSR) of medium-term aging and long-term aging. In the end, the paper gave a summary of evaluating system on asphalt mixture surface performance of skid-resistant wearing course, which is used to guide its design. |
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