【作者】 金祖权； 孙伟； 张云升； 蒋金洋；

【Author】 Jin Zuquan Sun Wei Zhang Yunsheng Jiang Jinyang (Department of Materials Science and Engineering, Southeast University, Nanjing 210096, China)

【机构】 东南大学材料科学与工程系；

【摘要】 通过快速碳化试验,研究了不同粉煤灰掺量(0~60%)、不同养护龄期(1,3,7,28,90d)、不同弯曲荷载率(0,25%,50%)对m(W)/m(C)=0.34混凝土的碳化影响,并建立了综合考虑粉煤灰掺量、养护龄期、荷载率、环境温度、结合能力以及混凝土的CO2扩散系数时间依赖性的多因素寿命预测模型.结果表明:混凝土的CO2扩散系数与粉煤灰掺量成二次函数关系,粉煤灰掺量30%左右最佳.混凝土的CO2扩散系数随养护龄期的增加而降低,随荷载率的增加而增加.其关系分别符合指数关系和乘幂关系.使用多因素碳化寿命预测模型对大桥的箱梁和索塔进行预测,箱梁的运营寿命为211年,索塔为167年.增加养护龄期或提高保护层厚度是提高大掺量粉煤灰结构混凝土寿命的重要途径.更多还原

【Abstract】 Based on accelerated carbonation test, effect of replacing ratio of fly ash (0-60%), curing age (1, 3, 7, 28 and 90 d), and loading ratio (0, 25% and 50%) on carbonation of concrete, while m(W)/m(C)=0.34, were studied. A multi-factor service life prediction model was proposed, in which the replacing ratio of fly ash, curing age, loading ratio, temperature, binding capacity and age factor of diffusion coefficient of CO2 were considered. Results show that the relation of diffusion coefficient of CO2 to replacing ratio of fly ash, curing age and loading ratio are corresponding to quadratic equation, exponent equation and power equation, respectively. Service lives of the box beam and bridge pylon of major bridge are 211 and 167 years based on multi-factor service life prediction model. Increase of curing age and cover size is the key to improve service life of concrete with high replacing ratio of fly ash.更多还原