正交异性钢桥面沥青混凝土铺装层的裂缝分类及成因

开裂是钢桥面铺装在使用过程中所面临的主要病害之一。报道了国内外10多座钢桥桥面沥青混凝土铺装层开裂状况的跟踪调查与分析结果。根据裂缝的分布位置与几何特征,将裂缝分为规则裂缝、U型裂缝、不规则短发丝裂纹及放射状裂纹4大类,归纳总结了各类裂缝的扩展规律并探讨了其原因。结果表明,规则裂缝是与正交异性钢桥面系构造特性密切相关的结构性问题;不规则短发丝裂纹及放射状裂纹则与施工缺陷密切相关,放射状裂纹主要由鼓包引起;U型裂缝为滑移型缝,层间界面的粘结强度与抗剪强度不足及混合料的高温稳定性不足是导致该类裂缝的主要原因。

Classification and Causes of Cracking of Asphalt Concrete Wearing Surfacing on Steel Orthotropic Bridge Decks

Cracking of the asphalt surfacing on steel decks will do great harm not only to the surfacing itself but also to the steel structure.The in-site crack survey on asphalt concrete wearing surfaces of more than ten bridges are reported,including gussasphalt,SMA with polymer modified asphalt and epoxy asphalt.The cracks are classified into four types according to its characters of geometry and location,with the names of regular cracks,unregular short hair cracks,bubble cracks and slippage cracks.Causes of the cracking of asphalt surfacing on steel orthotropic decks are discussed.Regular cracking is believed to be a fatigue matter according to 3-D Finite Element Analysis.Unregular short hair cracking and bubble cracking are mainly related to construction defects,while slippage cracking is primarily due to the interlayer lack of bonding strength and shear resistance and the wearing course lack of high temperature stability.