周期性半正矢荷载下沥青混合料的粘弹性本构模型(英文)

Viscoelastic model for asphalt mixture under repeated haversine load

通过引入应变硬化变量,对Burgers模型中串联粘壶进行了改进,并将改进模型看成是由Van Der Poel模型与改进粘壶串联组成.采用半正矢波间歇荷载模拟实际轮载作用,综合运用流变学和粘弹性力学理论推导了周期性荷载作用下沥青混合料永久变形的力学模型.然后根据3种沥青混合料的室内重复荷载永久变形试验结果,对该模型进行了验证.结果表明:随着荷载作用次数的增加,残余粘弹性应变占永久应变的比例先迅速衰减,而后逐渐趋向稳定,一般仅占2%～3%.荷载间歇时间越长,残余粘弹性应变越小.实际行车荷载的间歇时间足够长,因此残余粘弹性应变可以忽略,从而得到了简化模型.该模型可以很好地描述重复荷载下沥青混合料的永久变形特性.

The series-wound dashpot of the Burgers model is modified by introducing the strain hardening parameter, and the new model is considered as a combination of the modified dashpot and the Van Der Poel model. The cyclical pulse load consisting of a haversine load time and a rest period is adopted to simulate the actual vehicle load, and the permanent strain model under the repeated load is derived from the rheological and viscoelastic theories. Subsequently, the model is validated by the results of uniaxial repeated load permanent deformation tests of three asphalt mixtures. It is indicated that the proportion of residual viscoelastic strain to permanent strain decreases gradually with the load cycles, and only accounts for 2% to 3% during most of the loading period. If the rest period is long, the residual viscoelastic strain is little. The rest period of the actual vehicle load may be long enough, so the residual viscoelasticity can be ignored and the simplified model can be obtained. The proposed model can well describe the permanent deformation of asphalt mixtures under repeated load.