桥梁用C55混凝土弹性模量时变规律研究

Research on time change regulation of elastic modulus of C55 concrete for bridges

研究不同龄期和不同养护条件下弹性模量的时变规律对于早龄期混凝土结构构件的应变挠度计算、施工控制等具有重要意义。本文采用C55混凝土分别进行标准养护和同条件养护试验,测量其弹性模量,并进行数学模型拟合。结果表明:相对于指数函数而言,对数函数更契合C55混凝土弹性模量发展规律变化,弹性模量随时间呈增长趋势,早龄期阶段增长较快,后期趋于稳定。同时,结合实桥有限元仿真模型进行验证,结果表明,将预应力张拉作业提前至C55混凝土养护龄期为7 d乃至5 d是可行的。

The study of the time change regulation of elastic modulus at different ages and under different conservation conditions is important for the calculation of strain deflection and construction control of early-age concrete structural members.C55 concrete is used to carry out standard conservation and same-condition conservation tests,its elastic modulus is measured,and mathematical model fitting is carried out.The results show that the logarithmic function fits better with the change of the elastic modulus development law of C55 concrete than the exponential function,and the elastic modulus tends to grow with time,with faster growth at the early age stage and stabilization at the later stage.At the same time,combined with the finite element simulation model of the solid bridge,the results show that it is feasible to advance the prestress tensioning operation to the C55 concrete maintenance age of 7 d or even 5 d.