多因素影响下机制砂混凝土碳化深度研究及预测模型  

Research and prediction model of carbonization depth of mechanized sand concrete under multiple factors

作　　者：费壮 顾瑞[1] 万瑞 刘凯 张高展 FEI Zhuang;GU Rui;WAN Rui;LIU Kai;ZHANG Gaozhan(Jiangsu China Construction Ready Mixed Concrete Co.,Lid.,Nanjing 210033,China;School of Materials and Chemical Engeering,Anhui Jianzhu University,Hefei 230009,China)

机构地区：[1]江苏中建商品混凝土有限公司,江苏南京210033 [2]安徽建筑大学材料与化学工程学院,安徽合肥230009

出　　处：《混凝土》2025年第3期142-147,共6页Concrete

基　　金：国家自然科学基金(U21A20149)。

摘　　要：为探究内外部多因素影响下机制砂混凝土碳化深度的发展规律,利用快速碳化试验,研究了水泥及矿物掺合料用量、水胶比及外加剂掺量、石粉含量、细度模数、养护时间和CO_(2)浓度影响下不同碳化龄期的机制砂混凝土碳化速率,并结合扫描电镜进行微观结构分析.结果表明:粉煤灰替换量由0增至40%,快速碳化28 d后混凝土碳化深度增加90%;当水胶比大于0.45时,快速碳化14 d后碳化深度仍保持较大幅度增长;机制砂石粉含量增加,混凝土碳化深度呈先下降后上升趋势,石粉含量为10%时,28 d碳化深度为最小值;机制砂细度模数增加,各龄期碳化深度随之增加;养护时间对机制砂混凝土抗碳化性能提升尤为重要;混凝土前期碳化速率受CO_(2)浓度影响大,当CO_(2)浓度超过20%,后期碳化速率无明显差距;混凝土碳化深度随抗压强度增加而减小,二者存在较好的相关性;微观结构观察证实了适宜石粉含量对机制砂混凝土碳化前后性能具有提升作用.最后,基于试验结果进行多元非线性分析,建立了考虑内外部多因素的机制砂混凝土碳化深度预测模型,可为机制砂混凝土耐久性预测提供参考。In order to investigate the development law of carbonization depth of manufactured sand concrete under the influence of internal and external multiple factors,rapid carbonization tests were used to study the carbonization rate of manufactured sand concrete at different carbonization ages under the influence of cement and mineral admixtures dosage,water to binder ratio and additive dosage,stone powder content,fineness modulus,curing time,and CO2 concentration,and combined with the scanning electron microscope for the microstructural analysis.The results showed that the replacement amount of fly ash increased from 0 to 40%,and the carbonation depth of concrete increased by 90%after 28 days of rapid carbonation.When the water to binder ratio is greater than 0.45,the carbonization depth still maintains a significant increase after 14 days of rapid carbonization.The content of machine-made sand powder increases,and the carbonation depth of concrete shows a trend of first decreasing and then increasing,stone powder content in 10%,the carbonation depth at 28 days is the minimum.The fineness modulus increases,and the carbonization depth at all age increases accordingly.The curing time is particularly important for the improvement of carbonation resistance of manufactured sand concrete.Concrete carbonation rate in the early stage is greatly affected by CO2 concentration,when the CO2 concentration exceeds 20%,there is no significant difference in the later carbonation rate.The carbonation depth of concrete decreases with the increase of compressive strength,and there is a good correlation between the two.The microstructure observation confirms that the appropriate content of stone powder has an improvement effect on the performance of manufactured sand concrete before and after carbonization.Finally,based on the experimental results,a multivariate nonlinear analysis was conducted to establish a prediction model for the carbonation depth of manufactured sand concrete considering multiple internal and external factors,which

关 键 词：机制砂混凝土 碳化深度 石粉含量 微观结构 预测模型 

分 类 号：TU528.041[建筑科学—建筑技术科学]