大跨径水泥混凝土桥梁沥青铺装层结构组合研究

以五河口大桥桥面铺装层受力薄弱处沥青混合料为研究对象,选取5种结构类型组合,通过复合板双层车辙试验和复合梁疲劳试验,更精确地模拟实际受力状况,并进行了劈裂试验、冻融劈裂试验以及低温小梁等常规路用性能试验,为铺装层结构选择提供依据。研究结果表明:在结构组合设计中,重点考虑铺装上层的抗车辙性能,对于铺装下层混合料设计则更多的关注其他的路用性能;综合考虑组合结构的抗疲劳性能、抗拉性能、抗水损害性能和低温抗裂性能,桥面铺装下层宜选用粒径较小的级配,添加纤维效果尤佳。综合比较路用性能指标,考虑桥面实际施工状况和经济性,铺装上层采用玄武岩SMA-13沥青混合料,推荐SMA-10沥青混合料作为桥面沥青铺装下层。

Research on the Structure Combination for Long-span Concrete Bridge Asphalt Deck

Taking the asphalt mixture of the weakness point on the Wuhekou bridge deck as research object,the actual situation of five compsite structures were simulated more accurately by different board thicknesses compound board rutting test and compound beam fatigue test.Then split test,low-temp bend test and freezing-thawing split test were conducted to provide the basis for choosing the structure.It is indicated that,the rut resistance of asphalt mixture used in upper layer and the other road performance of asphalt mixture used in lower layer in structure design should be mainly considered;for anti-fatigue properies,tensile properties,anti-water damage propeties and anti-crack properies comprehensively,the gradation with a smaller aggregate size should be adopted for lower layer and the effects will be better if fiber is added;for road comprehensive performance of compound structures,construction and economics,SMA13 is recommended as the upper layer of bridge deck while SMA10 as the under layer.