铝锆偶联剂改善生物沥青混合料水稳定性研究

Research on water stability of bio-asphalt mixture modified by aluminum-zirconium coupling agent

为了提高生物沥青与石灰岩集料的黏附性,采用铝锆偶联剂对石灰岩集料进行改性.采用改进水煮试验、接触角试验分析铝锆偶联剂对生物沥青与石灰岩集料黏附性的影响;基于红外光谱和扫描电子显微镜试验分析微观变化和改性机理;采用沥青混合料水稳定性试验对石灰岩集料性能变化进行验证.结果表明,在0.2%铝锆偶联剂掺量下的15 min水煮试验中,生物沥青质量损失率相较改性前降低了20.52%;铝锆偶联剂使石灰岩集料由亲水性转变为亲油性,生物沥青与石灰岩集料的配伍率提升;红外光谱表明改性石灰岩集料表面引入了铝锆偶联剂的有机长链;扫描电子显微镜观测发现,铝锆偶联剂能在石灰岩集料表面形成薄膜,完成化学包裹;改性后的生物沥青混合料的残留稳定度与冻融劈裂强度比相较于改性前分别提升了7.91%与12.63%.

In order to improve the adhesion between bio-asphalt and limestone aggregate,aluminum-zirconium coupling agent is used to modify limestone aggregate.The improved boiling test and contact angle test are used to analyze the effect of aluminum-zirconium coupling agent on the adhesion of bio-asphalt and limestone aggregate.Microscopic changes and modification mechanisms are analyzed based on infrared spectroscopy and scanning electron microscopy tests.The water stability test of asphalt mixture is used to verify the variation of limestone aggregate properties.The results show that in the 15 min boiling test,under 0.2%of aluminum-zirconium coupling agent content,the mass loss rate of bio-asphalt is reduced by 20.52%compared with that before modification.The aluminum-zirconium coupling agent changes the limestone aggregate from hydrophilic to lipophilic,and the compatibility rate of bio-asphalt and limestone aggregate is improved.Infrared spectroscopy shows that the modified limestone aggregate surface introduces organic long chains of the aluminum-zirconium coupling agent.Scanning electron microscopy observation shows that the aluminum-zirconium coupling agent can form a thin film on the surface of the limestone aggregate to complete the chemical wrapping.The residual stability and freeze-thaw splitting strength ratio compared with those before modification are increased by 7.91%and 12.63%,respectively.