导电沥青混凝土的桥面铺装开裂预警技术研究

Research on Early Warning Technology of Cracking of Conductive Asphalt Concrete on Bridge Deck Pavement

沥青混凝土桥面铺装层在低温条件下极易产生开裂,空气中水分、灰尘等通过裂缝深入到桥面板与铺装层中间,会进一步造成层间滑移、水损坏。为及时对沥青混凝土桥面铺装的低温开裂病害进行预警,降低后期维修养护费用,采用碳纤维、石墨制备了复合导电沥青混凝土,并通过间接拉伸蠕变试验研究了其变形发展与电阻率的变化关系,根据曲线特点利用多项式拟合获得了不同蠕变阶段其力-电机敏特性。结果表明:碳纤维-石墨导电沥青混凝土电阻率与应变在不同阶段分别呈现出二次非线性、线性相关关系。同时,结合实体工程设计了分布式光纤传感器布设方案与施工流程,即在桥面铺装层间布设分布式光纤,上面层铺筑碳纤维-石墨导电混凝土,形成一种新型桥面铺装结构,为沥青混凝土桥面铺装低温开裂预警提供了一种全新的思路。

The asphalt concrete pavement layer is easy to crack under low temperature conditions.Moisture and dust in the air penetrate the crack to the middle of the bridge deck and the pavement layer,which will further cause slippage and water damage between the layers.In order to warn the low temperature cracking of asphalt concrete bridge pavement in time and reduce the cost of later maintenance,in this paper carbon fiber and graphite is usedto prepare composite conductive asphalt concrete,and its deformation development and resistivity are studied through indirect tensile creep test.According to the characteristics of the curve,the force-motor sensitivity characteristics of different creep stages are obtained by using polynomial fitting.The results show that the carbon fiber-graphite conductive asphalt concrete exhibits a quadratic non-linear and linear correlation between resistivity and strain at different stages.At the same time,the distributed fiber optic sensor layout plan and construction process are designed in combination with the physical engineering,that is,the distributed optical fiber is laid between the bridge deck pavement layers,and the upper layer is covered with carbon fiber-graphite conductive concrete to form a new bridge deck pavement structure,which providesa new idea for early warning of low-temperature cracking of asphalt concrete bridge pavement.