Field-blending approach is widely employed by the industry to introduce crumb rubber into asphalt binder. Rubber-modified binder provides satisfactory performance and benefits the environment by consuming recycled rubber manufactured from scrap tires. This work investigated the aging mechanism and post-aging performance of rubber-modified binders using laboratory aging protocols. Four rubber-modified binders containing two rubber contents (5 and 10 percent) and two particle sizes (passing 1.18 mm and 2.36 mm, respectively) were evaluated in this study. After multiple laboratory aging protocols, chemical components in aged binders were measured with Fourier transform infrared spectroscopy. Chemical analysis revealed that rubber-modified binders accumulated fewer oxidative aging products (carbonyl and sulfoxide components) than their unmodified base binder after long-term aging. Increasing rubber content and particle size increased the complex shear modulus while decreasing the phase angle of the binder. Binder viscosities were back-calculated from complex moduli and phase angles. A linear correlation between logarithmic viscosity and carbonyl area index exists for the long-term aged rubber-modified binders. This linearity can be used to predict the age-hardening of rubber-modified binders. These binders were also tested in dynamic shear rheometer to determine performance grades. Multiple stress creep recovery tests evaluated the rutting resistance of short-term aged binders. Bending beam rheometer was used to evaluate the low-temperature cracking resistance of long-term aged binders. These test results showed that rubber-modified binders provided better rutting and cracking resistance than their base binder. Statistical analysis indicated that carbonyl components correlated to the binder performance at various aging statuses.

中文翻译：

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现场共混胶粉改性粘结剂的实验室老化评价

业界广泛采用现场掺混方法将胶粉引入沥青粘合剂中。橡胶改性粘合剂通过消耗废旧轮胎制造的再生橡胶来提供令人满意的性能并有利于环境。这项工作使用实验室老化方案研究了橡胶改性粘合剂的老化机制和老化后性能。本研究评估了四种橡胶改性粘合剂，其中含有两种橡胶含量（5% 和 10%）和两种粒径（分别超过 1.18 毫米和 2.36 毫米）。经过多个实验室老化方案后，使用傅里叶变换红外光谱仪测量老化粘合剂中的化学成分。化学分析表明，长期老化后，橡胶改性粘合剂比未改性的基础粘合剂积累了更少的氧化老化产物（羰基和亚砜成分）。增加橡胶含量和粒度会增加复数剪切模量，同时减小粘合剂的相角。粘合剂粘度由复数模量和相位角反算。对于长期老化的橡胶改性粘结剂，对数粘度和羰基面积指数之间存在线性相关性。这种线性可用于预测橡胶改性粘合剂的时效硬化。这些粘合剂还在动态剪切流变仪中进行了测试以确定性能等级。多次应力蠕变恢复试验评估了短期老化粘合剂的抗车辙性能。采用弯曲梁流变仪评价长期老化粘结剂的低温抗裂性能。这些测试结果表明，橡胶改性粘合剂比其基础粘合剂具有更好的抗车辙和开裂性能。统计分析表明，羰基成分与不同老化状态下的粘合剂性能相关。