Cao Jiashuo, Wang Lifeng
School of Civil Engineering and Transportation, Northeast Forestry University, Harbin 150040, China.
Polymers (Basel). 2024 Oct 18;16(20):2924. doi: 10.3390/polym16202924.
In order to investigate the relationship between the molecular structure of fibers and the differences in physicochemical interactions between fibers and asphalt on the performance of fiber-modified asphalt, this paper chose two types of fibers with different chemical structures: straw fiber and polyester fiber. First, the differences in molecular interactions between the two fibers and asphalt were explored using molecular dynamics, then the differences in the adsorption capacity of the two fibers on asphalt components were tested by attenuated total reflection infrared spectroscopy experiments, and finally, the differences in the rheological properties of the two fiber-modified asphalts were tested by dynamic shear rheology and low-temperature creep experiments. The molecular dynamics simulation findings reveal that polyester fibers may intersperse into asphalt molecules and interact with them via structures such as aromatic rings, whereas straw fibers are merely adsorbed on the asphalt's surface. Straw fibers and asphalt exhibit hydrogen bonding, whereas polyester fibers and asphalt display van der Waals interactions. The results of attenuated total reflectance infrared spectroscopy indicated that polyester fiber absorbed asphalt components better than straw fiber. The rheological tests revealed that the polyester fiber had the highest complex shear modulus in the temperature range of 46-82 °C, and at 64 °C, the phase angle was 4.289° lower than that of the straw fiber-treated bitumen. Polyester fiber-modified asphalt had a 32.48%, 15.72%, and 6.09% lower creep modulus than straw fiber-modified asphalt at three low-temperature conditions: -6 °C, -12 °C, and -18 °C. It is clear that fibers with aromatic rings as a chemical structure outperform lignin-based fibers in terms of improving asphalt characteristics. The research findings can serve as a theoretical foundation for the selection of fibers to produce fiber-modified asphalt.
为了研究纤维的分子结构与纤维和沥青之间物理化学相互作用的差异对纤维改性沥青性能的影响，本文选择了两种化学结构不同的纤维：秸秆纤维和聚酯纤维。首先，利用分子动力学探究了两种纤维与沥青之间分子相互作用的差异，然后通过衰减全反射红外光谱实验测试了两种纤维对沥青组分的吸附能力差异，最后通过动态剪切流变和低温蠕变实验测试了两种纤维改性沥青的流变性能差异。分子动力学模拟结果表明，聚酯纤维可能会穿插到沥青分子中，并通过芳香环等结构与它们相互作用，而秸秆纤维只是吸附在沥青表面。秸秆纤维与沥青表现出氢键作用，而聚酯纤维与沥青表现出范德华相互作用。衰减全反射红外光谱结果表明，聚酯纤维对沥青组分的吸附能力优于秸秆纤维。流变测试表明，在46-82℃温度范围内，聚酯纤维的复数剪切模量最高，在64℃时，相角比秸秆纤维改性沥青低4.289°。在-6℃、-12℃和-18℃三个低温条件下，聚酯纤维改性沥青的蠕变模量比秸秆纤维改性沥青分别低32.48%、15.72%和6.09%。显然，以芳香环为化学结构的纤维在改善沥青性能方面优于木质素基纤维。研究结果可为纤维改性沥青生产中纤维的选择提供理论依据。
