水泥乳化沥青-旧沥青界面微尺度力学性质原位表征

In-situ characterization of microscale mechanical properties of interface between cement emulsified asphalt and aged asphalt

为探究乳化沥青冷再生混合料中水泥乳化沥青-旧沥青复合胶凝体系界面微尺度力学性质,利用基于原子力显微镜(AFM)的峰值力纳米力学性质量化(PF-QNM)技术和动态剪切流变试验,对不同材料组成条件下界面微尺度力学性质的演变规律和复合体系宏观流变特性进行了研究,建立了二者的关联性模型.结果表明:通过水泥乳化沥青和旧沥青力学性质的连续梯度变化可以量化表征界面作用范围;当旧沥青针入度小于15(0.1 mm)且水泥质量分数为1.0%~2.0%时,“黑石”假定基本成立;在宏观尺度上,复合体系流变性能与界面微尺度模量关联性较好;当旧沥青针入度小于30(0.1 mm)时,相同水泥用量下复合体系抗疲劳性能较为接近,适当降低水泥用量可较大程度上改善复合体系的抗疲劳性能.

To study the interface microscale mechanical properties of the cement emulsified asphalt-aged asphalt composite cementitious system in the cold recycled mixture with emulsified asphalt,the evolution law of the interface microscale mechanical properties and the macro rheological properties of the composite cementitious system under different material composition conditions were studied by the peakforce quantitative nano-mechanics(PF-QNM)technology based on atomic force microscope(AFM)and the dynamic shear rheological tests.A correlation model was established.The results show that the continuous gradient changes of the micromechanical properties of the cement emulsified asphalt and the aged asphalt can quantify the interface effect range.When the penetration of the aged asphalt is less than 15(0.1 mm)and the cement mass fraction is 1.0%to 2.0%,the“black aggregate”assumption is basically true.On the macroscopic scale,the rheological property of the composite system has a good correlation with the microscale modulus analysis results on the interface.When the penetration of the aged asphalt is less than 30(0.1 mm),the anti-fatigue performance of the composite system is relatively close under the same cement dosage.Thus,appropriately reducing the cement dosage can improve the anti-fatigue performance of the composite system.