温度应力、自收缩对高性能混凝土早期开裂的影响

Effect of Thermal Stress and Autogenous Shrinkage on Early Age Cracking of High Performance Concrete

根据高性混凝土的水化特性、物理力学特性及自收缩特性,分析了高性能混凝土早期开裂机理和影响早期开裂的主要因素.并结合工程实例,借助混凝土温度和应力有限元仿真计算方法分析研究了表面适度保温和水管冷却技术在高性能混凝土温控防裂中的应用效果.研究结果表明,表面适度保温与水管冷却相结合能有效降低混凝土的内外温差,减小混凝土早期表面拉应力与后期内部拉应力,防裂效果明显,对类似的工程具有借鉴作用.

The mechanism of early age cracking in the high performance concrete（HPC） and its main influential factors are analyzed based on the hydration characteristic and mechanical characteristics of HPC and the characteristics of autogenous shrinkage. The prevention steps are presented. With an engineering example the effect of external moderate heat preservation and internal cooling pipes on perfocention from HPC cracking is studied by using the finite element method for temperature and thermal stress simulation calculation. The results show that this measure can reduce effectively the inner-outer temperature difference; the early age surface tensile stress and the internal tensile stress. The effectiveness of prevention from early age cracking of HPC is achieved; and the results should have great referential significane to similar projects in the future.