为预防核电站大体积混凝土在早期出现收缩开裂的情况,本文采用双重调控技术优化设计混凝土配合比(温度场和膨胀历程调控)替代布置冷却水管的抗裂方案,对核电站混凝土裂缝进行控制.配合比中选择P·N 42.5水泥、大掺量矿物掺合料和掺量8%的抗裂剂,其中,抗裂剂具有降低早期水化放热速率以及全过程补偿混凝土收缩变形的作用,同时制备的混凝土的工作性能、力学性能及耐久性均满足设计要求.结果表明:经过有限元仿真抗裂风险计算分析,采用抗裂方案的核电站主体结构,开裂风险系数小于0.7,混凝土基本不会开裂,符合设计施工要求.
To prevent shrinkage and cracking of large volume concrete in nuclear power plants at an early stage,this paper adopts dual control technology to optimize the design of concrete mix proportions(temperature field and expansion process control)instead of the anti-cracking scheme of arranging cooling water pipes,in order to control concrete cracks in nuclear power plants.It selects P·N 42.5 cement,high content mineral admixture,and 8%anti-cracking agent as the mix proportion of concrete.Among them,the anti-cracking agent has the effect of reducing the early hydration heat release rate and compensating for the shrinkage deformation of concrete throughout the process.Meanwhile,the working performance,mechanical properties and durability of concrete meet the design requirements.The results show that through finite element simulation and crack resistance risk calculation analysisthe main structure of nuclear power plant with anti-cracking scheme,the cracking risk coefficient is less than 0.7,and the concrete will not crack basically,which meets the design and construction requirements.