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针对水泥混凝土结构在服役期间经历干旱、降雨等自然现象的交替作用所产生的体积变化,选择在温度、湿度交变[35℃,相对湿度(relative humidity)Rh=30%;20℃,Rh=100%]试验条件下评价减缩剂对水泥石体积稳定性的影响,并采用核磁共振和压汞仪分析其机理。结果表明:减缩剂通过提高水泥石在温度、湿度交变环境的水化程度、增大水化硅酸钙凝胶的聚合程度,同时降低水泥石的可逆、不可逆收缩及最大长度变化,减小在严酷干燥条件的干缩值及潮湿环境的湿胀值,提高在恶劣自然环境保持较高体积稳定性的能力。
According to the change of volume caused by the alternation of natural phenomena such as drought and rainfall during the service, cement concrete structure was selected under the conditions of alternating temperature and humidity [35 ℃, relative humidity Rh = 30%, Rh = 100%] to evaluate the influence of shrinkage reducing agent on the volume stability of cement stone under the experimental conditions. The mechanism of the shrinkage reducing agent was analyzed by NMR and mercury porosimetry. The results show that the shrinkage reducing agent can increase the degree of hydration of hydrated calcium silicate gel by increasing the degree of hydration of cement stone in the alternating environment of temperature and humidity and reduce the reversible and irreversible shrinkage and the maximum length of hydrated calcium silicate gel, Dry shrinkage in harsh dry conditions and wetting in humid environments increase the ability to maintain high volumetric stability in harsh natural environments.