Chemical, thermophysical, rheological, and microscopic characterisation of rubber modified asphalt binder exposed to UV radiation
Chemical, thermophysical, rheological, and microscopic characterisation of rubber modified asphalt binder exposed to UV radiation
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DOI：
10.1080/14680629.2020.1736606
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发表时间：
2020-03
影响因子：
3.7
通讯作者：
Mehdi Zadshir;Desiree Ploger;Xiaokong Yu;C. Sangiorgi;H. Yin
中科院分区：
文献类型：
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作者：
Mehdi Zadshir;Desiree Ploger;Xiaokong Yu;C. Sangiorgi;H. Yin
本文研究了紫外线对掺有橡胶粉的沥青结合料试样的影响。使用PG 64-22纯粘合剂表征两组样品，其中橡胶颗粒的不同百分比为0、16.6和20.0重量%。一组样品在环境温度下储存（称为未老化组），另一组样品插入加速老化试验机内100小时（称为UV老化组）。分别采用闪蒸法、差示扫描量热仪（DSC）、傅里叶变换红外光谱仪（FTIR）、动态剪切流变仪（DSR）和扫描电镜（SEM）对两组样品的导热系数、化学指标、流变性和形态进行了测试。结果表明，橡胶的加入导致了橡胶改性粘结剂比热的降低。三种紫外老化样品的比热容均大于未老化样品，其中16.6%老化样品的比热容最大。三个未老化样品的FTIR光谱非常相似，而UV暴露后发生明显变化。UV老化后，与S = O基团相关的峰的归一化吸光度增加，脂肪族基团的峰降低，显示出由于UV老化而氧化的一些证据。在粘合剂中使用废橡胶末降低了导热系数，并且20.0重量%与16.6重量%相比，样品的导电性甚至更低。在高于25°C的所有温度下，老化样品的热导率低于未老化样品，除了纯粘合剂相反。流变学测试表明，样品的复模量随着橡胶颗粒的加入而增加，老化后也增加。然而，16.6%的橡胶改性样品显示出老化后模量的最小增加。微观形态表明，紫外线辐射导致纯和橡胶改性粘合剂中的裂纹。可以看到形成较小的裂纹，并且在橡胶改性的粘合剂中裂纹碎片粘在一起，而在纯粘合剂中观察到裂纹之间的内聚性较小。
In this work, the effect of ultraviolet (UV) radiation on samples of asphalt binder mixed with crumb rubber is studied. Two sets of samples are characterised using a PG 64-22 neat binder with different percentages of rubber particles being 0, 16.6, and 20.0 wt.%. One set of the samples was stored at ambient temperature (called the unaged set) and the other was inserted inside an accelerated weathering tester for 100 h (called the UV-aged set). Thermal conductivity, chemical indices, rheology, and morphology of both sets of samples are tested using the flash method, differential scanning calorimeter (DSC), Fourier-Transform Infrared Spectroscopy (FTIR), dynamic shear rheometer (DSR), and Scanning Electron Microscope (SEM), respectively. Results show that the addition of rubber leads to a reduction of specific heat for the rubber-modified binders. Specific heat capacities of the three UV aged samples are larger than those of their unaged counterparts, and the 16.6%-aged has the highest value. FTIR spectra of the three unaged samples are very similar, whereas distinct changes occur after UV exposure. The normalised absorbance of the peak associated with S = O group increases and the peak for the aliphatic group decreases after UV aging, showing some evidence of oxidation due to UV aging. Use of crumb rubber in the binder decreases the thermal conductivity and 20.0 wt.% sample is even less conductive compared to the 16.6 wt.%. At all temperatures above 25°C, aged samples have lower thermal conductivity than the unaged ones, except neat binder which is opposite. Rheological measurements show that the complex modulus of the samples increases with the addition of rubber particles and also after aging. However, 16.6% rubber-modified sample shows the least increase in modulus after aging. Microscopic morphology shows that UV radiation causes cracks in both neat and rubber modified binder. Smaller cracks are seen to form, and the cracked pieces are stuck together in the rubber modified binders, whereas less cohesion between the cracks is observed in the neat binder.