粉煤灰喷射混凝土孔隙结构的演变特征  

Evolutionary Characteristics of Pore Structure of Fly Ash Shotcrete

作　　者：张俊儒[1] 闻毓民[1,2] 欧小强 ZHANG Junru;WEN Yumin;OU Xiaoqiang(Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031,China;National Engineering Laboratory for Technology of Geological Disaster Prevention in Land Transportation,Chengdu 610031,China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室土木工程学院,四川成都610031 [2]陆地交通地质灾害防治技术国家工程实验室,四川成都610031

出　　处：《西南交通大学学报》2018年第2期296-302,共7页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金资助项目(51378435)

摘　　要：为了寻找长期服役的喷射混凝土配合比,采用低场核磁共振技术,研究了不同粉煤灰掺量改性胶凝材喷射混凝土的微观孔隙结构,测定了不同掺量的粉煤灰喷射混凝土在不同养护龄期的微观孔隙结构分布特征及孔隙度.研究结果表明:掺有粉煤灰的喷射混凝土孔隙度随粉煤灰掺量的增加而增大,随龄期的延长总体呈现先减小后趋于平稳的趋势;粉煤灰掺量为10%时孔隙度最小,掺量为0时孔隙度最大;在7 d龄期后,不同粉煤灰掺量的喷射混凝土内部孔隙半径主要在1~80 nm的范围内,该半径范围内的孔隙含量占总孔隙含量的80%,最可几孔半径在12 nm.To study the mixture ratio of pore structure in fly ash shotcrete during operation,low-field magnetic resonance imaging technology was adopted. The micro-pore structure of the modified cementitious shotcrete with different fly ash content was investigated. The micro-pore size distribution characteristics and porosity of shotcrete with different fly ash content,at different curing phases were measured. The results show that the porosity of the fly ash shotcrete increases with an increase in the fly ash content; however,with increase in the curing age,the porosity generally decreases first,and subsequently tends to be stable. The results also indicate that the value of porosity is minimum and maximum when the amount of fly ash is 10% and 0,respectively. After the 7-day healing period,the inner pore radius of shotcrete varies from 1 to 80 nm for different proportions of fly ash. In such a radius range,the value of micro-pore is 80% of the total fissure value. The most probable pore radius is approximately 12 nm.

关 键 词：喷射混凝土 低场核磁共振 粉煤灰 孔径分布 孔隙度 

分 类 号：TU528.53[建筑科学—建筑技术科学]