碳化和氯离子共同作用下复合改性硫氧镁水泥基材料损伤机理研究

复合改性硫氧镁（CMMO）水泥基材料实际上是一种对传统未改性硫氧镁水泥进行复合改性后而获得的高抗裂、高耐水性及抗侵蚀性能更优异的新型硫氧镁水泥基材料。本项目拟立足典型海洋大气环境特征，确定与气体和离子传输机制密切相关的CMMO水泥基材料的微细观结构参数,确定CMMO水泥基材料碳化反应机理，探明碳化和氯离子共同作用下CMMO水泥基材料微细观结构的损伤劣化机理，提出考虑碳化反应影响的基于微细观结构参数的CMMO水泥基材料氯离子传输模型；利用该模型可以准确地预测海洋大气环境中CMMO水泥基材料中氯离子浓度分布特征，并确定能够满足该类环境条件要求的高耐久性CMMO水泥基材料的关键微细观结构设计参数；从而最终切实解决海洋大气环境中混凝土结构的耐久性失效问题。

Composite modified magnesium oxysulfate (CMMO) cement-based material actually is a new type of magnesium oxysulfide cement-based material with high cracking resistance, water resistance and corrosion resistance, which is obtained by modifying traditional unmodified magnesium oxysulfide cement with compound additives. Based on the characteristics of typical marine atmospheric environment, this project intends to determine the micro-structural parameters of CMMO cement-based materials closely related to gas and ion transport mechanism, determine the carbonization reaction mechanism of CMMO cement-based materials, explore the damage and degradation mechanism of the micro and meso structures of CMMO cement-based materials under the combined action of carbonization and chloride ions, and propose a chloride ion transport model for CMMO cement-based materials based on micro-meso-structural parameters considering the effect of carbonization reaction. Adopting this model the distribution characteristics of chloride ion concentration in CMMO cement-based materials in marine atmospheric environment, can be accurately predicted and the key micro-structural design parameters of CMMO cement-based materials which can meet the requirements of this kind of environmental conditions can be determined; Finally the durability failure problem of concrete structures in marine atmospheric environment can be effectively solved.