槽和黏层油对沥青混合料层间抗剪性能的影响

Effect of Notch and Tack Coat on the Interface Shear Performance between Asphalt Layers

为确定沥青路面面层界面两侧材料组合(A)、界面压槽(B)、黏层油(C)及其交互作用(A×B,A×C,B×C)对层间抗剪性能影响的主次顺序和显著性,根据正交试验方法设计试验方案,进行试验研究.采用击实法制备了3种类型的复合式马歇尔试件,试件的下层为AC-20,上层分别为AC-13、AC-20、OGFC-13.3种类型试件的界面情况分别为无槽无黏层油、无槽有黏层油、有槽无黏层油和有槽有黏层油.利用自制的沥青混合料层间剪切仪对试件进行了常温下(25℃)的直接剪切试验.结果表明:相比于界面无任何措施的层间抗剪强度,黏层油,槽以及二者的联合3种工艺对界面名义抗剪强度的平均增加率分别为23.8%、42.9%及53.9%;3个因素及其交互作用对界面抗剪性能影响的主次顺序为:A、B、C、B×C、A×C、A×B;其显著性为:A、B、C及因素B、C的交互作用B×C对层间抗剪强度的影响为高度显著因素,交互作用A×B与A×C为次要因素.

In order to evaluate the important order and significance of the type of asphalt mixtures （A） on both sides of the interface of pavement surface course, the notch （B） in the interface, the tack coat （ C ）, and the two-way interactions （ A x B, A x C and B x C ） of the three factors that influence the interlayer shear strength, the orthogonal design was applied to make the test scheme. Three types of composite Marshall specimens were prepared by compaction method. The lower layer of specimens was 19 mm nominal maximum aggregate size （NMAS） dense-graded asphalt mixture （AC-20） ; and the upper layer was 13 mm NMAS dense-graded asphalt mixture （AC-13）, AC-20, or 13 mm NMAS open-graded friction courses （OGFC-13）, respectively. There were four treatments for the specimens interfaces, namely, neither notch nor tack coat （NNNT）, no notch but tack coat （ NNYT）, no tack coat but notch （ YNNT）, and both notch and tack coat （YNYT）. The interfaces of the specimens were directly sheared by the homemade interface shearing apparatus at 25 ℃. The results show that the average shear strength of the NNYT, YNNT, and YNYT interface is increased by 23.8% , 42.9% , and 53.9% respectively, compared with the average shear strength of the NNNT interface. By variance analysis, the effect of the three factors and their interactions on the shear bond strength can be ranked in a descending order as A, B, C, B × C, A × C, and A × B. The A, B, C, and the interaction of B x C are highly significant factors, and the interactions A × B and A × C are subordinate factors.