冻融循环作用对乳化沥青冷再生混合料抗剪性能的影响

针对乳化沥青冷再生混合料进行反复冻融循环试验,测定不同冻融循环周期后试件的空隙率、贯入剪切强度及无侧限抗压强度,分析冻融循环作用下乳化沥青冷再生混合料力学性能、抗剪强度参数的衰变规律,同时通过扫描电镜(SEM)观察经冻融循环后的混合料微观形貌。结果表明:经过10次冻融循环后,空隙率增大1%,力学强度下降幅度达到20%,而对冷再生混合料粘聚力影响最大,其下降幅度可达到60%;冻融循环过程中产生的膨胀应力及温度应力破坏了混合料内部水泥水化产物形成的立体网状结构,导致冷再生混合料力学性能及抗剪强度参数的衰减。

Study on Impacts of Freeze-thaw Cycles on the Shear Performances of Emulsified Asphalt Cold Recycle Mixture

After making a repeated freeze-thaw cycle test over emulsified asphalt mixture, the air void, penetration shear strength and unconfined compressive strength were tested under different freeze-thaw cycle times to analyze performance attenuation regularity. Meanwhile, SEM was tested to observe the microstructure after 15 times freeze-thaw cycles. The result indicated that after 10 freeze-thaw cycles, void volume increased 1%, the mechanical strength decreased up to 20%, and the cohesive decreased up to 60%. The three-dimensional network structure formed by cement hydration products were destroyed which caused the attenuation of mechanical properties and shear strength parameters, due to the expansion and temperature stress.