抗裂防水剂在北京地铁5#线高架桥箱梁混凝土中的应用研究

本文研究了抗裂防水剂对地铁5#线高架桥C50箱梁强度、孔结构、限制膨胀率的影响。试验结果表明：一定掺量的抗裂防水剂对高强混凝土的补偿收缩效果明显，能使混凝土的限制膨胀率达到规范要求，混凝土的结构密实。早期和后期强度都能得到提高；掺量过高时，混凝土的强度降低；孔结构和SEM形貌图表明：当抗裂防水剂掺量为11％时，混凝土大孔减少，小孔增多，孔结构得到较好改善，总孔隙率降低，混凝土结构致密。

Anticrack and water-resisting admixture applied in cased concrete beam of over bridge for Beijing Metro No. 5

It researched on the influence of anticrack and water-resisting admixture to C50 cased beam strength, cavernous structure and limited expansion rate of overbridge of Beijing Metro No. 5. The result shows appropriate amount of admixture can compansate shrinkage of high stregnth concrete evidently, and make the limited expansion rate to standard, improve the concrete structure compactness, early and late strength. The more the admixture, the lower the concrete strength. It shows, from the cavernous structure and SEM, the admixture is 11 % , the big hole decreased and small hole increased. The total porosity factor is lowered, structure of concrete is compact.