基于等效龄期的机制砂高性能混凝土强度快速评价方法与工程应用

Rapid strength evaluation method and engineering application of machined sand high performance concrete based on equivalent age

大体积混凝土结构受水化温升的影响,结构内部温度显著高于环境温度,结构内部混凝土的强度发展规律与同条件养护试件存在一定差异。针对C40~C60三种强度等级机制砂高性能混凝土,研究了20~80℃养护温度对机制砂混凝土抗压强度的影响规律,结果表明:高温养护加快了机制砂高性能混凝土早龄期抗压强度的发展,但对于80℃养护温度,高温养护对混凝土后期的抗压强度有不利影响;建立了等效龄期与机制砂高性能混凝土抗压强度、抗拉强度之间的函数模型,大体积混凝土实测结果与计算值较为吻合,在大体积混凝土结构开裂风险分析时,应考虑结构内部温升的影响。

Internal temperature of mass concrete structure is significantly higher than the ambient temperature due to hydration caused temperature rise. There are some differences between strength development law of concrete inside mass structure and curing specimen under site maintenance. Effects of curing temperatures at 20~80 ℃ on compressive strength of concrete were studied for C40~C60 three strength grade high performance concrete. Result show that high temperature curing accelerates development of early age compressive strength. However,high temperature curing had adverse negative influence on the later period compressive strength for curing temperature of 80 ℃. Function model between equivalent age and compressive strength,tensile strength of high performance concrete were established. Measured results of mass concrete agree well with the calculated values. Influence of internal temperature rise should be considered at analysis of cracking risk of mass concrete structure.