普通硅酸盐混凝土高温性能劣化分析模型

Analysis Model on Deterioration of Ordinary Silicate Concrete under High Temperature

混凝土材料的高温力学性能劣化规律是混凝土结构防火设计及灾后评估的重要依据。基于普通硅酸盐混凝土材料内部各组分在高温作用下的微观物理化学变化,研究了硬化水泥浆中水化物高温分解和骨料材料性能的劣化过程,揭示了混凝土在高温作用下宏观力学性能劣化的机理,建立了用于描述普通硅酸盐混凝土高温力学性能劣化规律的分析模型,在传统模型仅能考虑温度大小影响的基础上进一步考虑温度持续时间对材料力学性能劣化的影响。利用FLAC3D软件中的FISH语言开发了相应的计算程序,并用于分析混凝土试块在不同温度和时间作用下材料抗压强度和弹性模量等随温度的劣化规律,与现有试验结果对比表明模型能够合理反映混凝土在高温作用下材料性能的劣化过程。

The deterioration of mechanical properties of concrete at high temperature plays an important role in fire prevention design and assessment of concrete structure after fire. On the basis of the microscopic physical and chemical changes of inner components in concrete,the thermal decomposition process of hydrates and the thermal damage process of aggregate at high temperature were studied,and then an analysis model for material properties description of concrete at high temperature was put forward. This model can not only take into account the influence of temperature amplitude as traditional methods,but also consider the impact of temperature duration. The corresponding computer program was developed by the FISH language in the fast Lagrangian analysis of continua(FLAC3 D). The program was then used to analyze the change law of compressive strength and elastic modulus of test blocks under different temperature amplitude and temperature duration. The simulation results agree well with those of experimental tests. It indicates that the model is correct and feasible.