纳米碳酸钙/废旧聚乙烯功能化复合改性沥青性能影响及机理研究

Study on properties and mechanism of asphalt modified with nano⁃calcium carbonate/waste polyethylene composite

为了进一步改善纳米碳酸钙(nano‑CaCO_(3))、废旧聚乙烯(WPE)单独改性沥青的成本及技术缺陷,本文通过三异硬脂酰基酞酸异丙酯(TTS)作为偶联剂,采取螺杆挤出造粒技术制得nano‑CaCO_(3)/TTS/WPE共混体系改性剂(CTW)及其改性沥青。重点研究了不同含量TTS对CTW改性沥青性能影响并对改性机理进行分析。结果表明,随着TTS含量的增加,CTW改性沥青软化点、延度、黏度先增大后基本保持不变,针入度变化则相反。动态剪切流变性及低温性能研究表明,一定含量的TTS有利于改善CTW改性沥青的高低温性能,同时对上述性能变化进行微观形貌及机理分析,可能的原因在于,不同含量TTS与nano‑CaCO_(3)/废旧聚乙烯/asphalt材料间物理、化学协同作用导致其性能变化。

To further modify the high cost and technical defects of asphalt separately modified with nano‑calcium carbonate(nano‑CaCO_(3))and waste polyethylene(WPE),the nano‑CaCO_(3)/TTS/WPE composite modifier(CTW)and CTW‑modified asphalt were prepared through melt extrusion using isopropyl triisostearyl phthalate(TTS)as a coupling agent.The influence of TTS content on the properties of CTW‑modified asphalt was studied,and the modification mechanism was analyzed.The analysis of conventional indexes indicated that the softening point,elongation,and viscosity of the CTW‑modified asphalt increased at first and then kept stable with an increase in the TTS content.However,the penetration degree exhibited an opposite change.According the investigation on the dynamic shear rheology and low temperature properties,a certain amount of TTS was conducive to improving the high‑and low‑temperature properties of the CTW‑modified asphalt.Meanwhile,microtopography and mechanism analysis was carried out for the above‑mentioned changes in the properties,and the results indicated that the physical and chemical interactions between different contents of TTS and nano‑CaCO_(3)/WPE/asphalt led to the performance changes of the CTW‑modified asphalt.