废植物油再生沥青结合料性能研究

Properties of Waste Vegetable Oil Recycled Asphalt Binder

为解决传统矿物油沥青再生剂稳定性差、价格高等问题,采用煎炸后的废植物油(WVO)对老化沥青进行再生,研究不同掺量的废植物油对老化沥青物理性能指标、高温流变性质、低温弯曲流变性质和微观结构特性的影响。结果表明:随着废植物油掺量的提高,老化沥青的延度及针入度逐渐升高,软化点及布式黏度逐渐降低;相位角δ逐渐增大,复数剪切模量G^(*)和车辙因子G^(*)*/sinδ逐渐减小,沥青结合料抗车辙能力下降;同时老化沥青的蠕变劲度模量S值降低,蠕变速率m值升高,低温抗开裂能力提高。为保证再生沥青有良好的高低温性能,推荐废植物油掺量控制在7%~10%范围内。老化及废植物油的再生,引发了沥青微观结构特征的演变,废植物油的再生作用恢复了老化沥青中的"蜂形"结构,沥青表面高度及表面粗糙度增加。由老化及再生作用引起的沥青微观结构特征演变与宏观流变性能之间存在可量化表征的相关关系。

In order to solve the problems of unstable and high price of traditional mineral oil asphalt regenerant,the waste vegetable oil(WVO)after frying was used to regenerate the aged asphalt.The effects of different amounts of WVO on physical properties,high temperature rheological properties,low temperature bending rheological properties and microstructure characteristics of the aged asphalt were studied.The results show that with the increase of the amount of WVO,the ductility and penetration of the aged asphalt gradually increase,while the softening point and brookfield viscosity gradually decrease;the phase angle(δ)gradually increases,the complex shear modulus(G*)and the rutting factor(G*/sinδ)decreases gradually,and the rutting resistance of the asphalt binder decreases.At the same time,the creep stiffness modulus(S)of the aged asphalt decreases,the creep rate(m)increases,which means the low temperature cracking resistance of asphalt binder increases.In order to ensure that the recycled asphalt has good high and low temperature performance,it is recommended that the amount of WVO is controlled within the range of 7%to 10%.Aging and regeneration of WVO leads to the evolution of the microstructure characteristics of asphalt.The regeneration of WVO restores the“bee-shaped”structures in aged asphalt,and the surface height and surface roughness of asphalt increase.There is a quantifiable correlation between the evolution of microstructure characteristics and macro rheological properties of asphalt caused by aging and regeneration.