Zhang Yongjun, Liu Xiu, Yin Boyuan, Luo Wenbo
College of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China.
Hunan Key Laboratory of Geomechanics and Engineering Safety, Xiangtan University, Xiangtan 411105, China.
Polymers (Basel). 2021 Apr 14;13(8):1278. doi: 10.3390/polym13081278.
The mechanical behavior of asphalt mixture under high stresses presents nonlinear viscoelasticity and permanent deformation. In this paper, a nonlinear fractional viscoelastic plastic (NFVEP) creep model for asphalt mixture is proposed based on the Nishihara model, with a Koeller spring-pot replacing the Newton dashpot. The NFVEP model considers the instantaneous elasticity, viscoelasticity with damage and time-hardening viscoplasticity with damage concurrently, and the viscoelastic response is modeled by fractional derivative viscoelasticity. To verify the model, uniaxial compressive creep tests under various stresses ranging from 0.4 MPa to 0.8 MPa were carried out at room temperature. The NFVEP model predictions are in good agreement with the experiments. The comparison with the modified Nishihara model and the Burgers model reveals the advantages of the NFVEP model. The results show that the NFVEP model, with the same set of parameters, can not only describe the primary and steady-state creep stages of asphalt mixture under low stress levels but also the whole creep process, including the tertiary creep stage, of asphalt mixture under high stress levels.
沥青混合料在高应力下的力学行为呈现出非线性粘弹性和永久变形。本文基于西原模型，提出了一种沥青混合料的非线性分数阶粘弹塑性（NFVEP）蠕变模型，用科勒尔弹簧 - 壶体取代牛顿阻尼器。NFVEP模型同时考虑了瞬时弹性、带损伤的粘弹性和带损伤的时间硬化粘塑性，粘弹性响应采用分数阶导数粘弹性建模。为验证该模型，在室温下进行了0.4MPa至0.8MPa不同应力水平下的单轴压缩蠕变试验。NFVEP模型预测结果与试验结果吻合良好。与修正西原模型和伯格斯模型的比较揭示了NFVEP模型的优势。结果表明，NFVEP模型在参数相同的情况下，不仅能描述低应力水平下沥青混合料的初始蠕变阶段和稳态蠕变阶段，还能描述高应力水平下沥青混合料的整个蠕变过程，包括第三阶段蠕变。
