冻融作用下聚氨酯透水混合料性能衰减规律

Properties Decay Law of Polyurethane Permeable Mixtures under Freeze-thaw Action

为研究冻融作用对聚氨酯透水混合料(polyurethane bounded permeable mixture,PUPM)性能的影响,通关相应宏观试验对PUPM冻融损伤特性进行多尺度表征。首先测定PUPM质量损失率、吸水率、劈裂强度随冻融次数变化的衰减规律;在不同冻融阶段进行拉拔试验,分析冻融过程中界面抗拉强度的衰减规律及界面破坏形态的变化。试验结果表明,冻融过程中,相比于开级配磨耗层(open graded wear layer,OGFC),PUPM质量损失率较大;PUPM吸水率先增大后减小,之后趋于平缓;PUPM的劈裂强度与胶石界面抗拉强度前期衰减较快,后期衰减减缓;冻融初期,胶石界面从粘聚破坏转变为粘附破坏,水的侵蚀是造成界面损伤的重要原因。

In order to study the effect of freezing-thawing action on the properties of polyurethane bounded permeable mixture(PUPM),multi-scale characterization of freezing-thawing damage characteristics of PUPM was carried out through corresponding macro tests.First,the decay law of PUPM mass loss rate,water absorption rate and splitting strength with freeze-thaw times were measured;Drawing tests were carried out in different freezing-thawing stages to analyze the attenuation law of interface tensile strength and the change of interface failure mode during freezing-thawing.The results show that,in freeze-thaw process,PUPM mass loss rate is higher than open graded wear layer(OGFC).PUPM water absorption firstly increased and then decreased,and then tended to be flat.The splitting strength of PUPM and the tensile strength of colloidal interface attenuate rapidly in the early stage and slow down in the late stage.At the early stage of freezing-thawing,the interface of colloidal stone changes from cohesive failure to adhesive failure,and water erosion is an important reason for the interface damage.