松针油再生沥青流变性能与再生机理研究

Study on rheological properties and regeneration mechanism of pine needle oil recycled asphalt

针对废植物油再生沥青存在抗老化性能和抗高温性能较差等问题,以松针油为基础油分复配增塑剂制备一种生物再生剂,并与废植物油再生剂进行了对比。通过沥青三大指标试验分析沥青老化及再生后的物理性能;基于动态剪切流变仪(DSR)和弯曲梁流变仪(BBR)试验分别评价了再生沥青及其二次老化后高温和低温流变性能;并使用傅里叶变换红外光谱试验测定松针油再生剂及沥青官能团结构,分析松针油再生沥青的机理。结果表明:当老化沥青中掺加8%松针油及2%邻苯二甲酸二辛酯时,老化沥青三大指标基本得以恢复至基质沥青水平。相比废植物油再生沥青,松针油再生沥青显示出更好的高低温流变性能,且松针油再生沥青经二次老化后各项性能也都优于基质沥青老化后的性能。松针油具有和沥青相近的官能团,与沥青相融后可以补充老化沥青中缺失的轻质组分,从而改善再生沥青胶体结构,使其恢复良好性能。邻苯二甲酸二辛酯作为增塑剂主要作用是通过润滑沥青分子以降低其低温下运动阻力,从而改善沥青低温性能。松针油基再生剂不仅能够提升老化沥青流变性能,且保证再生沥青具有良好抗二次老化性能的耐久性。

Aiming at the problems of poor anti-aging performance and high-temperature performance of waste vegetable oil recycled asphalt,a biological regenerant was prepared by using pine needle oil as the base oil and compounding plasticizer,as well as compared with the waste vegetable oil regenerant.The plasticizer used in this study was dioctyl phthalate.The physical properties of asphalt after aging and regeneration were analyzed by the three basic indexes(penetration,softening point and ductility)of asphalt.The test results showed that when 8%pine needle oil and 2%dioctyl phthalate were added into aged asphalt,the physical properties of aged asphalt basically returned to the level of matrix asphalt.Based on the dynamic shear rheometer(DSR)and bending beam rheometer(BBR)tests,the high-temperature and low-temperature rheological properties of recycled asphalt and its secondary aging were evaluated,respectively.The results showed that when compared with waste vegetable oil recycled asphalt,the pine needle oil recycled asphalt showed better high-and low-temperature rheological properties,and the high-and low-temperature rheological properties of pine needle oil recycled asphalt were better than those of matrix asphalt.This indicated that pine needle oil regenerant could also improve the performance of recycled asphalt by improving the rutting resistance and low-temperature crack resistance of recycled asphalt.In addition,the performance of aged recycled asphalt was also better than that of aged matrix asphalt,indicating that pine needle oil regenerant also could improve the anti-aging performance of recycled asphalt by slowing down the aging rate of recycled asphalt and prolonging its service life.The structures of pine needle oil regenerant and asphalt functional groups were determined by Fourier transform infrared spectroscopy,and the regeneration mechanism of pine needle oil on asphalt was analyzed.The analysis results showed that pine needle oil had similar functional groups as those of asphalt,and could supplement the missing light components in aged asphalt after melting with asphalt,thereby improving the colloidal structure of recycled asphalt and restoring its good performance.The main role of dioctyl phthalate as a plasticizer was to reduce the movement resistance at low temperature by lubricating asphalt molecules,thereby improving the low-temperature performance of asphalt.The pine needle oil-based regenerant not only could improve the rheological properties of aged asphalt,but also ensure the durability of recycled asphalt with good secondary aging resistance.