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高模量沥青混合料以其优异的抗车辙效果而广受关注,尤其是添加剂型高模量沥青混合料,然而添加剂对沥青混合料性质的影响作用机理尚不明确。以傅里叶红外光谱仪(FIR)、沥青抽提仪、扫描电子显微镜(SEM)、动态剪切流变仪(DSR),研究高模量添加剂在沥青混合料中的作用机理。通过FT-IR官能团分析添加剂对沥青的影响,分析添加剂与石料的相互作用及沥青混合料性能,对高模量添加剂添加前后的沥青粘弹特性差异及沥青混合料性能进行对比分析。研究结果表明:长链脂肪族碳链的酯类与聚烯烃接枝复配的添加剂,不损伤沥青混合料低温抗裂性;拌和时熔点在150℃~160℃,粒径较小的添加剂B与热集料(180℃~190℃)碰撞、被剪切并熔融分散,沥青抽提后其在石料表面残留少,贡献率较高;SEM图像显示添加剂B在沥青中分散均匀,且灰度直方图的灰度值较集中;DSR研究发现,熔融的添加剂使沥青弹性模量G′增大,相位角δ降低,粘度增大,改善了沥青流变特性;少量未熔融颗粒碾压时嵌挤入混合料空隙中,增大了混合料内摩阻角,提高了沥青混合料的模量。
The high modulus asphalt mixture attracts much attention due to its excellent anti-rutting effect, especially the additive-type high modulus asphalt mixture. However, the mechanism of the effect of additive on the properties of asphalt mixture is not clear. The mechanism of action of high modulus additive in asphalt mixture was studied by Fourier transform infrared spectrometer (FIR), asphalt extraction instrument, scanning electron microscopy (SEM) and dynamic shear rheometer (DSR). The effects of additives on asphalt were analyzed by FT-IR functional groups. The interaction between additives and stone and the properties of asphalt mixture were analyzed. The viscoelastic properties difference of asphalt before and after the addition of high modulus additive and the performance of asphalt mixture were analyzed. The results show that the long chain aliphatic carbon chain esters and polyolefin grafted additives do not damage the low temperature cracking resistance of asphalt mixture; when the melting point is 150 ℃ ~ 160 ℃, the smaller particle size additive B Collided with hot aggregate (180 ℃ -190 ℃), was sheared and melted and dispersed. After asphalt was extracted, it remained less on the surface of the stone with a higher contribution rate. SEM images showed that additive B was uniformly dispersed in asphalt and the grayscale Histogram of the gray value of the more concentrated; DSR study found that molten additives to the asphalt elastic modulus G 'phase angle δ decreases, the viscosity increases, improving the rheological properties of bitumen; a small amount of unmelted particles rolling embedded Squeezed into the gap in the mixture, increasing the friction resistance within the mixture, increasing the modulus of asphalt mixture.