含层间界面的复合小梁疲劳性能影响因素的交互作用

Study of Influential Factors on Fatigue Performance of Composite Asphalt Mixture Beams with Bonded Interface

为探讨在车辆荷载重复作用下,铺面材料疲劳性能的变化规律,采用含有层间界面的复合小梁进行四点弯曲疲劳试验。通过改变复合小梁的材料组合方式、黏层油类型及用量,以及应变水平等影响因素,测定复合小梁试件的疲劳寿命。结果表明:(1)对于双层均为密实型材料的复合小梁,各因素对其疲劳寿命的影响大小顺序为黏层油用量>应变水平>黏层油类型,对于上层为空隙型、下层为密实型的复合小梁,各因素影响顺序为应变水平>黏层油用量>黏层油类型;(2)随着上层沥青混合料空隙的增大,层间黏结性能下降,复合小梁疲劳寿命减小,而随着黏层油用量的增加,层间黏结性能先增后减,复合小梁的疲劳寿命也先增后减;(3)混合料级配类型及材料性质在影响复合小梁疲劳寿命的因素中居主导地位,SMA-13与SMAP-5的结构组合整体性最好,疲劳寿命最大;(4)确定了复合小梁疲劳寿命与黏层油用量之间的相互关系,并采取现象学法疲劳模型,建立疲劳寿命方程。

In order to investigate the fatigue behavior of asphalt pavement under dynamic loading, 4-point bending fatigue test is carried out on composite asphalt mixture beams with bonded interface. The major test parameters considered in this study to acquire the fatigue life of composite beam specimens are the type of asphalt mixture material, tack coat type and application rate, and the strain level. The results show that. （1） for double-layer beams with dense type mixture the order of influence of each factor on its fatigue life ranks as tack coat application rate 〉 the strain level 〉 tack coat type. On the other hand, for hi-layer beams composed of gap-graded mixture type as the upper layer and dense-graded mixture type as the lower layer, the impact of the factors in descending order ranks as the strain level 〉 tack coat application rate 〉 tack coat type; （2） both the interface bonding strength and the fatigue life of asphalt mixture decrease with increasing voids content in the upper layer. Apart from this, as tack coat application rate increases the values of the aforementioned measured parameters reach to peak and then decrease accordingly; （3） the gradation type and material properties of the mixture are the main factors which influence the fatigue life of composite beams. The structure combination of SMA-13 and SMAP-5 exhibits the best structural integrity and outperforms other asphalt mixtures with respect to fatigue life; and （4） the relationship between the fatigue life and tack coat application rate is determined, and the fatigue life equation is established using the phenomenological method.