为了实现海洋大气环境中粉煤灰混凝土耐久性使用寿命的预测,从氯离子在人工模拟海洋大气环境中粉煤灰混凝土中的传输试验出发,结合氯离子在非饱和多孔介质中的传输机理,研究海洋大气环境下混凝土内部微环境(微环境温度和相对湿度)及粉煤灰掺量对氯离子传输速率的影响程度,并与人工模拟海洋水下环境试验结果进行对比分析.研究结果表明:1)在海洋大气环境与海洋水下环境下,氯离子在粉煤灰混凝土中的扩散模型形式上一致,粉煤灰的掺入对氯离子传输能力有一定的影响,但不会改变氯离子在混凝土中的传输机理.2)当粉煤灰掺量一定时,微环境相对湿度越高(微环境温度一定),海洋大气环境氯离子扩散系数越大;但微环境温度(微环境相对湿度一定)对海洋水下环境和海洋大气环境中氯离子迁移的影响程度不同.3)粉煤灰掺量(微环境温度、相对湿度一定)对海洋水下环境和海洋大气环境氯离子扩散系数的影响规律不同.
The effect of micro-environment(temperature and relative humidity inside the concrete) and fly ash replacement on chloride ion transport in the fly ash concrete was analyzed from test results in artificial marine atmospheric zone and chloride diffusion mechanism in non-saturated porous media in order to predict durability service life.Then a comparative analysis between marine atmospheric environment and marine underwater environment was conducted.Results show that: 1)the form of chloride diffusion model in fly ash concrete under atmosphere environment is consistent with that under underwater marine environment;the fly ash has a certain effect on chloride ion transport capacity,but it does not change the transport mechanism of chloride ion transport in fly ash concrete.2)the higher the micro-environment relative humidity is(the same micro-environment temperature),the greater chloride ion diffusion coefficient in atmosphere environment is;the effect of the micro-environment temperature(the same micro-environment relative humidity) on chloride ions transport in the atmospheric zone differs from that in underwater zone.3) fly ash replacement(the same micro-environment temperature and relative humidity) affects differently the chloride diffusion coefficient under marine atmospheric environment and underwater environment.