摘   要：实际工程新老混凝土粘接时，老混凝土龄期可能从初凝至数十年。目前，对短龄期老混凝土与新混凝土粘接劈拉强度研究较少，本文在不同界面剂、不同浇筑结合方式下研究了老混凝土龄期从初凝至28d的新老混凝土的粘结劈拉强度，发现粘结劈拉强度随老混凝土龄期增大而减少，并逐渐趋于稳定；界面剂的使用提高了新老混凝土的粘结劈拉强度，水泥砂浆界面剂的效果略优于水泥净浆界面剂；水平结合的劈拉强度均远大于竖直结合的劈拉强度；在机理分析的基础上拟合出粘结劈拉强度随老混凝土龄期变化的公式。

Abstract: Old-concrete age of new-to-old concrete may be from initial setting to decades in the actual project. At present, studying on bond splitting strength of the new-concrete-to-short-age-old is less, considering different interface cementing agent, different combination method, the new-to-old concrete bond splitting strength rule which old-concrete age from initial setting to 28d is studied in this paper, and it is found that bond splitting strength increases with old-concrete age decreasing, and then gradually stabilized. The splitting strength of new old concrete bond can be improved though using interface cementing agent, mortar interface cementing agent is slightly better than that of cement paste interface cementing agent. The splitting strength of level combination is far greater than vertical combination. Based on mechanism analysis, the bond splitting strength with old-concrete age changing formula is fitted.