热固型缓凝粘合剂实际张拉适用期和实际有效强度期估算方法

Method for estimating actual tensile pot life and actual effective strength period of thermosetting retarding adhesives

缓粘结预应力混凝土结构中,热固型缓凝粘合剂的实际张拉适用期和实际有效强度期是决定缓粘结钢绞线的张拉时间和结构正常使用时间的重要条件。分析了影响热固型缓凝粘合剂实际张拉适用期和实际有效强度期的主要因素,选定了三个不同标准固化期的热固型缓凝粘合剂作为试验材料,制作一定数量的锥入度和邵氏硬度试件。通过试验,得到了相同温度条件下,热固型缓凝粘合剂固化期与实际张拉适用期和实际有效强度期的比例关系,建立起锥入度、邵氏硬度与时间关系曲线,以及实际张拉适用期、实际有效强度期与温度关系曲线。据此,提出了实际张拉试用期和实际有效强度期与温度关系的计算公式,并进行了工程实例验证。结果表明,计算公式可对缓粘结钢绞线的实际张拉适用期和实际有效强度期进行较准确的预测,对于工程应用具有一定的实用价值。

In the slowly bonded prestressed concrete structure,the actual tensile pot life and actual effective strength period of thermosetting retarding adhesive are important conditions to determine the tensioning time of slowly bonded steel strand and the normal service time of the structure.The main factors affecting the actual tensile pot life and actual effective strength period of thermosetting retarding adhesive were analyzed.Three thermosetting retarding adhesives with different standard curing periods were selected as test materials to make a certain number of cone penetration and shore hardness specimens.Through the test,the proportional relationship between the curing period of thermosetting retarding adhesive and the actual tensile pot life and actual effective strength period under the same temperature was obtained.The relationship curve between penetration,shore hardness and time,as well as the relationship curve between the actual tensile pot life,actual effective strength period and temperature were established.Based on this,the calculation formulas of the relationship between the actual tensile pot life,the actual effective strength period and temperature were put forward,and verified by an engineering example.The results show that the calculation formula can accurately predict the actual tensile pot life and actual effective strength period of slowly bonded steel strand,and has some practical value for engineering application.