基于三维细观空隙的超薄罩面层间洒布量设计与性能评价

Design and Performance Evaluation of Interlayer Dosage of Ultra-thinOverlay Based on Three-dimensional and Mesoscopic Void

为研究超薄罩面与原路面之间的层间黏结沥青洒布量,通过计算机断层扫描(computed tomography,CT)和三维重构技术对混合料试件进行空隙扫描和结构重建,依据空隙分布规律确定环氧沥青的填充空隙用量。在此基础上,结合室内25、60℃的层间45°斜剪、直剪以及拉拔试验,分析不同沥青洒布量对层间剪切和黏结强度的影响。结果表明:Novachip Type-A环氧沥青和SMA-13混合料的空隙均沿试样高度呈C型分布,有效空隙集中于表面2 mm以及底部1 mm,由此确定沥青填充空隙用量为0.25 kg/m~2。室内试验中满足最大层间剪切、黏结强度的沥青洒布量为0.7 kg/m~2,层间洒布量过少、过大时会发生黏附及黏聚破坏,因此最佳层间洒布量为0.95 kg/m~2。

In order to study the interlayer dosage of the ultra-thin overlay and original pavement,mixture specimens were scanned and reconstructed by computed tomography(CT)and three dimensional reconstruction technology.The dosage of epoxy asphalt filled was determined according to voids distribution.On this basis,effects of asphalt contents on the shear and bond strength were analyzed by the laboratory 45°oblique shear,direct shear and pulling tests at 25,60℃.Results show that voids of Novachip Type-A epoxy asphalt and SMA-13 mixture are C-shaped along the height of the sample,and effective voids are concentrated at the surface of 2 mm and the bottom of 1 mm,so the asphalt dosage filling voids is 0.25 kg/m 2.In laboratory tests,the interfacial asphalt satisfied the maximum shear and bond strength is 0.7 kg/m 2.Adhesion and cohesion destruct when the interfacial dosage is low or excess,so the optimal interlaminar dosage is 0.95 kg/m 2.