蜡基温拌剂对沥青微观特性的影响分析

Analysis of influence of wax-based warm mix agents on microscopic properties of asphalt

【目的】探讨蜡基温拌剂对沥青微观特性及蜡析出过程的影响。【方法】选择两种常用的商业蜡基温拌剂——Sasobit和Asphaltan作为研究对象,通过红外光谱试验定性分析温拌剂与沥青的混合机理,通过变温偏光显微镜试验定量分析蜡析出过程中蜡晶体的变化规律,从而深入探讨温拌剂在沥青中的作用机理及其对沥青中蜡析出过程的影响。【结果】相比于Sasobit,Asphaltan温拌剂还具有碳氧双键。蜡基温拌剂与沥青之间未发生复杂的化学反应,仅发生物理共溶。随着温度的降低,沥青的析蜡速率逐渐减小并最终趋于稳定。同时,蜡晶体的数量、平均粒径和面积分数均随着温度降低而增大。在晶体生长过程中,蜡晶体相互连接形成网络结构。此外,温拌沥青蜡析出过程受温度和降温速率的影响,较小的降温速率有助于形成更为完整、有序的蜡晶体。【结论】蜡基温拌剂在沥青中主要通过物理共溶作用影响蜡晶体的析出过程。通过优化降温速率,可以显著改善蜡晶体的结构和性能,从而提高温拌沥青的整体性能。

[Purposes]This study aims to explore the influence of wax-based warm mix agents on the microscopic characteristics of asphalt and wax precipitation.[Methods]Two commonly used commercial wax-based warm mix agents,Sasobit and Asphaltan,were selected as research objects.The mixing mechanism of warm mix agents and asphalt was qualitatively analyzed by infrared spectroscopy test,and the changes in wax crystals during wax precipitation were quantitatively analyzed by variable temperature polarizing microscope test.The mechanism of action of warm mix agents in asphalt and its influence on the process of wax precipitation in asphalt were deeply discussed.[Findings]Compared with Sasobit,the Asphaltan warm mix agent also has carbon-oxygen double bonds.There is no complex chemical reaction between wax-based warm mix agents and asphalt,and only physical co-solubility is observed.The wax precipitation rate of asphalt decreases with the decrease in the temperature and finally tends to be stable.At the same time,the number,average size,and area fraction of wax crystals increase.The wax crystals are connected to form a network structure as they grow.Moreover,the wax precipitation process in warm mix asphalts is affected by temperature and cooling rate.A slower cooling rate helps to form more complete and orderly wax crystals.[Conclusions]Wax-based warm mix agents affect the precipitation process of wax crystals in asphalt mainly through the physical co-solubility effect.Optimizing the cooling rate can significantly improve the structure and properties of wax crystals,thereby improving the overall performance of warm mix asphalt.