【摘要】 在恒温恒湿环境下,通过对粉煤灰混凝土试块进行增湿(正向扩散)、干燥(反向扩散)试验,研究了粉煤灰掺量、微环境条件对粉煤灰混凝土表层湿质扩散的影响,并建立了粉煤灰混凝土等效湿质扩散系数的预计模型.结果表明:在增湿和干燥过程中,粉煤灰混凝土微环境相对湿度响应速率逐渐变缓,湿质扩散系数逐渐减小;在微环境相对湿度相同条件下,15%掺量(质量分数)粉煤灰会使混凝土湿质扩散系数降低,但45%掺量粉煤灰会使混凝土湿质扩散系数明显增大;在粉煤灰混凝土微环境温度和初始内外相对湿度差相同情况下,反向等效湿质扩散系数明显比正向等效湿质扩散系数小.更多还原

【Abstract】 The effects of fly ash replacement and micro-environmental conditions on moisture diffusion in fly ash concrete surface layer were studied by humidification test(positive diffusion)and drying test(reversed diffusion)in constant temperature and humidity environment.The predicting model for equivalent moisture diffusion coefficients of fly ash concrete was created.The results show that in the humidification test and drying test,the micro-environment relative humidity response rate of fly ash concrete gradually slows down,while the moisture diffusion coefficient decreases gradually;15%(by mass)fly ash replacement reduces moisture diffusion coefficient of concrete under the same micro-environment relative humidity,but 45%fly ash replacement accelerates it.The reversed equivalent moisture diffusion coefficient is significantly smaller than the positive equivalent moisture diffusion coefficient in the same micro-environment temperature and initial relative humidity difference inside and outside the fly ash concrete.更多还原