Crumb rubber modified bitumen (CRMB) can be considered as a binary composite system where rubber particles are embedded in the bitumen matrix. The bitumen-rubber interaction process (mainly swelling) significantly changes the mechanical properties of both bitumen and rubber phases. This study aims to predict the complex moduli of CRMB binders with more representative constituent parameters using micromechanical models. To achieve this goal, frequency sweep tests using a dynamic shear rheometer were performed on the liquid phase of CRMB and swollen rubber samples to represent the essential properties of bitumen matrix and rubber inclusion. In addition, the numerical swelling model was developed to estimate the effective volume concentration of rubber after swelling. Results show that the liquid phases of CRMB are stiffer and more elastic than the neat bitumen while the swollen rubber is softer and more viscous than the dry rubber. The effective volume concentration of rubber can increase to 2.126 times as the blend percentage based on the finite element analysis. Using the liquid phase of CRMB binder and swollen rubber properties as the micromechanical model inputs yield more accurate predictions. The used four micromechanical models predict well at higher frequencies while underestimating the complex modulus at lower frequencies.

中文翻译：

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胶粉改性沥青复剪切模量的微观力学模拟

橡胶粒改性沥青 (CRMB) 可以被认为是一种二元复合系统，其中橡胶颗粒嵌入在沥青基质中。沥青-橡胶相互作用过程（主要是溶胀）显着改变了沥青和橡胶相的机械性能。本研究旨在使用微机械模型预测具有更具代表性的成分参数的 CRMB 粘合剂的复杂模量。为了实现这一目标，使用动态剪切流变仪对 CRMB 和溶胀橡胶样品的液相进行频率扫描测试，以表示沥青基质和橡胶夹杂物的基本特性。此外，还开发了数值溶胀模型来估计溶胀后橡胶的有效体积浓度。结果表明，CRMB 的液相比纯沥青更硬、更有弹性，而溶胀橡胶比干橡胶更软、更粘。根据有限元分析，橡胶的有效体积浓度可提高到共混百分比的2.126倍。使用 CRMB 粘合剂的液相和溶胀橡胶特性作为微机械模型输入可产生更准确的预测。所使用的四种微机械模型在较高频率下预测良好，而在较低频率下低估了复数模量。使用 CRMB 粘合剂的液相和溶胀橡胶特性作为微机械模型输入可产生更准确的预测。所使用的四种微机械模型在较高频率下预测良好，而在较低频率下低估了复数模量。使用 CRMB 粘合剂的液相和溶胀橡胶特性作为微机械模型输入可产生更准确的预测。所使用的四种微机械模型在较高频率下预测良好，而在较低频率下低估了复数模量。