基于静水压理论的混凝土冻融破坏演化模型

FREEZING-THAWING FAILURE EVOLUTION MODEL OF CONCRETE BASED ON HYDROSTATIC PRESSURE THEORY

定量分析混凝土材料的抗冻性能是数字混凝土时代的基本要求之一,在全面分析混凝土抗冻性能影响因素和现有混凝土冻融破坏假说的基础上,推导了混凝土冻融破坏理论模型,该模型以内因和外因为自变量,以材料的微、细观结构演变为核心,实现了混凝土抗冻性能的定量分析。模型计算分析表明:水泥水化产物物理力学性能、引气泡含量及孔径分布、最低温度、降温速率、应力水平、材料溢出距离等内、外因素,从不同角度、不同程度影响水泥基材料的冻融损伤特性,合理设计引气泡含量及引气泡孔径,方能有效提高混凝土的抗冻耐久性。且上述分析结果同已有研究成果有较好契合。研究成果能为混凝土的抗冻设计提供参考。

Quantitative analysis of frost resistance of concrete materials is one of the basic requirements of digital concrete era.Based on the comprehensive analysis of the factors affecting the frost resistance of concrete and the existing hypothesis of freeze-thaw damage of concrete,the theoretical model of freeze-thaw damage of concrete is deduced.The model uses internal and external independent variables,and takes the micro-structure evolution of the material as the core,so as to realize the quantitative analysis of the frost resistance of concrete.The calculation analysis of the model shows that the physical and mechanical properties,bubble content and pore size distribution,minimum temperature,cooling rate,stress level,material overflow distance and other internal and external factors of cement hydration products affect the freeze-thaw damage characteristics of cement-based materials from different angles and to different degrees.Reasonable design of bubble content and bubble aperture can effectively improve the frost resistance durability of concrete.The above analysis is in good agreement with the existing research results.The research results can provide reference for the freezing resistance design of concrete.