The Fengnan Bridge on Tianjing-Qinhuangdao Passenger Dedicated Railway spanning Tianjin-Shanhaiguan Railway is a double-track railway bridge. On part of the section of the bridge, the cement emulsified asphalt mortar (CA mortar) was used as the padding courses between the track slabs and the concrete bases or bearing surfaces. Before the mix proportioning of the mortar was designed, the materials for the mortar were firstly preliminarily chosen through a great amount of tests and the mortar was then designed by the orthogonal design method. The influences of 4 kinds of the materials (i. e. the emulsified asphalt, drier, defoaming agent and water-reducing agent) on the performance of the mortar were analyzed and the initial mix proportioning and the workmanship for mixing the mortar were determined. In the slab uncovering tests for the mortar mixed according to the initial mix proportioning, it was found that the air bulbs were two many and too big and the problems of the cavity and surface white strips existed. After adjusted, the final mixing proportioning was determined to be as the follows: the drier : emulsi fied asphalt : water reducing agent : defoaming agent : water=l 500 : 275 : 5. 0 — 5. 5 (adjustable) : 0. 5~0. 7 (adjustable) : 135 —145 (adjustable). The mortar was finally checked and verified and the results of the checking showed that the various indices of the mortar could meet its corresponding requirements.%津秦客运专线丰南跨津山特大桥为双线铁路桥,该桥部分段轨道板和混凝土底座或支承层之间的垫层采用水泥乳化沥青砂浆(CA砂浆).设计CA砂浆配合比时,通过大量试验,初步选定原材料,采用正交设计方法,分析4种原材料(乳化沥青、干料、消泡剂、减水剂)掺量对CA砂浆性能的影响情况,确定CA砂浆初始配合比及搅拌工艺.在对初始配合比砂浆进行揭板试验的过程中出现气泡过多、过大、空洞、表面有白色带状条的问题,经调整,最终确定CA砂浆基本配合比为干料:乳化沥青:减水剂:消泡剂:水=1 500:275:5.0～5.5(可调):0.5～0.7(可调):135～145(可调).对该配合比CA砂浆进行审核及验证,审核结果表明所检测的各项指标均满足相应要求.
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