基于粘弹特性的沥青损伤演化本构模型研究

Damage problem is the essential issue for the basic theory, design and maintenance of asphalt pavement, so the damage constitutive model of asphalt binders has been received a lot of attentions in the past few years. The key points to establish a damage constitutive model are viscoelastic model and damage evolution function. Until now, there are two issues about establishing a damage constitutive model. One is that the viscoelastic models are not universal; it is hard for the extant viscoelastic models to reflect different mechanical behaviors (including thixotropy) under dynamic or static loadings. The other is that it is difficult for the damage evolution function to reflect the damage essence of asphalt binders. In order to solve these problems, the viscoelastic characteristics of asphalt binders in time domain and Laplace domain are studied, and the standard curve spectrograms of viscoelastic characteristic parameters are drew. Based on that, the universal viscoelastic model is established. Based on the changing laws of the viscoelastic model parameters during damage process, the internal variables master curves are obained. Based on the the chaging law of the master curvers which reflect damage effects or thixotropy effects, the damage evolution law is analyzed, the unified damage variable is put forward, and the damage evolution function which can reflect the damage evolution essence of asphalt binder is established. By combing the damage evolution function and the universal viscoelastic model, the damage constitutive model of asphalt binders is established and verified. This research provides a theoretical basis for forecasting asphalt binder performance, and lays the foundation of damage constitutive model of asphalt mixtures. Besides that, it has reference value for the damage research of another viscoelastic materials.

损伤问题是沥青路面结构基础理论与设计维修的本源性问题，多年来沥青的损伤演化本构模型一直备受关注。损伤演化本构模型建立的关键在于粘弹模型的选择与损伤演化函数的建立。目前存在的主要问题是：粘弹模型不具有普适性，难以准确反映沥青动静载下的各种力学行为（包括触变性）；损伤演化函数难以反映沥青损伤的本质。针对以上问题，本项目从时域、拉氏域内沥青的粘弹特性入手，建立粘弹特征参数标准曲线谱图，在此基础上建立沥青普适粘弹模型；分析损伤过程中粘弹模型参数的变化规律，建立沥青内变量主曲线族；基于反映损伤或粘弹影响的不同主曲线族变化规律，分析沥青损伤演化规律，提出统一损伤变量，建立反映沥青损伤本质的损伤演化函数；结合损伤演化函数与普适粘弹模型建立沥青损伤演化本构模型并验证。 本研究为沥青性能的预测提供了理论依据，为沥青混合料损伤演化模型的建立奠定了基础。此外，对其它粘弹性材料损伤特性的研究具有一定的参考价值。

损伤问题是沥青路面结构基础理论与设计维修的本源性问题，多年来沥青的损伤演化本构模型一直备受关注。损伤演化本构模型建立的关键在于黏弹模型的选择和损伤演化函数的建立。目前存在的主要问题是：黏弹模型不具有普适性，难以准确反映沥青动静载下的各种力学行为；损伤演化函数难以反映沥青损伤的本质。针对以上问题，本项目首先详细分析了动、静载下沥青的线性黏弹特性，提出了黏弹模型的模型辨识和参数辨识方法，并根据黏弹参数变化规律和模型辨识方法，建立了沥青的四元件串联分数阶导数模型；然后，为分析沥青的损伤特性，提出了多阶段疲劳和多阶段蠕变损伤测试方法，分别分析了沥青疲劳和蠕变损伤过程中沥青黏弹特征参数的变化规律；结合参数的变化规律及其对损伤的敏感性，确定了沥青的损伤变量，构建了沥青的损伤函数；最后，结合沥青的普适黏弹模型和损伤函数，建立了沥青的损伤演化本构模型。本项目建立的普适黏弹模型可以准确描述沥青的动静态黏弹力学特性，克服了现有模型仅能反映部分黏弹力学行为的不足；构建的沥青损伤演化本构模型可以描述沥青的疲劳及蠕变损伤过程，为沥青性能的预测提供了依据。此外，项目的研究成果可用于沥青胶浆以及沥青混合料黏弹特性以及损伤模型的研究，为沥青混合料损伤演化模型的建立奠定了基础，也为其它黏弹材料损伤特性的研究提供了依据和参考。