(1. 南京航空航天大学 土木与机场工程系，江苏 南京，211106；
2. 江苏华通工程检测有限公司，江苏 南京，210011)
摘 要: 为了研究碱式硫酸镁水泥混凝土(MC)在桥梁拓宽连接中的受力性能，开展MC和普通硅酸盐水泥混凝土(NC)作为接缝的2组拼接箱梁模型的试验研究。研究结果表明：拼缝采用MC时，拼接段开裂后呈现多缝开裂破坏模式，破坏荷载比大于采用NC连接的破坏荷载比；MC接缝的裂缝宽度超过0.2 mm时仍缓慢增长且刚度逐步下降；而NC接缝的裂缝宽度超过0.2 mm时急剧增长且变形亦急剧增长，构件很快破坏；MC接缝比NC接缝具有更好的抗裂、变形和传力性能。
关键词: 拼接箱梁；碱式硫酸镁水泥混凝土；破坏荷载比；裂缝宽度；变形
（1. Department of Civil and Airport Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China;
2. Jiangsu Huatong Engineering Testing Co. Ltd., Nanjing 210011, China）
Abstract:In order to review the mechanical properties of basic magnesium sulfate cement concrete(MC) when it was used in bridge widening, two specimens of widened box girders with MC and normal Portland cement concrete (NC) as joint materials were studied in experimental way. The results show that the splicing section of MC presents a multi-joint cracking failure. The failure load ratio is larger than that of NC one. When the crack width exceeds 0.2 mm the crack width of MC section grows stably and the stiffness also descends slowly, while crack width of NC section grows spurt and the specimen cannot bear load soon. MC material has better crack and deformation resistance and load transfer performance than NC material.
Key words: spliced box girder; basic magnesium sulfate cement concrete; failure load ratio; crack width; deflection
