沟槽式新老混凝土粘结面抗剪强度试验研究

Experimental Research on Shear Strength of Interfacial Bonding of New and Old Concrete by Cutting Groove

采用自制的剪切夹具对72块150 mm×150 mm×150 mm沟槽式新老混凝土粘结试件进行了抗剪试验.研究了6种粗糙率沟槽处理方式,新混凝土等级,界面剂对新老混凝土粘结面抗剪性能的影响.结果表明,沟槽式新老混凝土粘结面具有较好的抗剪性能,其最佳平均灌砂深度为2.5 mm;其抗剪强度随着新混凝土强度等级增加而增大;水泥膨胀浆界面剂可使其抗剪强度达到整体的75%.最后,介绍了沟槽法在实际工程中的应用.近12年的实际运行表明,该新老混凝土叠合整修加固方法操作简单,便于施工及质量控制,经济可行.

In this paper, shearing test on 72 cube specimens（ 150mm × 150mm × 150mm） with cutting groove bonding has been carried out, using the self - made shearing equipment. Six type roughness of interfacial treating, type of young concrete and adhesion agent are studied on the interface of new and old concrete. The result indicates that the interfacial bonding of new and old concrete has good shearing property, the best average sand-pouring depth is 2.5mm; the shearing strength becomes big with new concrete stress class and the shearing strength of the interface with cement paste mixed with 12% U expanding agent is up to 75% of the total one. At last, the project example is introduced. Its twelve years＇ practical application proves that this bonding method of new and old concrete is suitable for the project.