摘要
研究了热水-干热组合养护制度对超高性能混凝土（UHPC）力学性能的影响,并通过扫描电子显微镜和X射线衍射技术,对经历该种组合养护后UHPC的微观结构进行了测定。结果表明：这种组合养护可以显著提高UHPC的力学性能;延长其中干热养护的持续时长或提高干热养护的温度,将更加有利于力学性能的提高。微观测试结果证实,组合养护使得UHPC内部生成了更加致密的C-S-H凝胶和少量托勃莫来石、硬硅钙石晶体。热水养护先形成了UHPC的致密结构框架,其后的干热养护在如此致密的结构框架中营造了一个高温蒸汽环境,达到了类似于蒸压养护的效果,激发了残余水泥颗粒的进一步水化和掺合料的火山灰反应,生成更多致密的水化产物,优化了UHPC的微观结构,进而显著提高其力学性能。
The influence of combined curing on mechanical properties of ultra-high performance concrete（UHPC） was investigated. The combined curing was composed of precuring in hot water and heating in dry air. Moreover, the microstructure of UHPC under the combined curing was also determined by scanning electron microscopy and X-ray diffraction. The results indicate that the combined curing improves the mechanical properties of UHPC remarkably, especially at prolonged duration and increased temperature of dry air heating. The results of microstructural tests show that denser C-S-H gels and a small amount of C-S-H crystals such as sheet-like tobermorite and needle-like xonotlite are formed in the UHPC subjected to the combined curing. During dry air heating in the combined curing, a high temperature steam environment（similar to that of autoclaving） can be established in the dense structure framework of UHPC formed in the preceding hot water curing. The further hydration of residual cement and pozzolanic reaction of mineral admixtures can be activated during dry air heating, leading to the formation of a large amount of dense hydration products that accumulate in the existing aforementioned framework. Therefore, the microstructure of UHPC is optimized and its mechanical properties are enhanced.
作者
牛旭婧
朋改非
尚亚杰
戴磊
戢文占
NIU Xujing;PENG Gaifei;SHANG Yajie;DAI Lei;JI Wenzhan(Faculty of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;Beijing Construction Engineering Group（BCEG）,Advanced Construction Materials Co.,Ltd.,Beijing 100015,China;China State Construction Engrg.Co.,Ltd.Technical Center,Beijing 101300,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2018年第8期1141-1148,共8页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(50978026,51078030,51278048)
北京市自然科学基金(8172036)
关键词
超高性能混凝土
组合养护
力学性能
微观结构
ultra-high performance concrete
combined curing
mechanical properties
microstructure
作者简介
牛旭婧（1989-），女，博士研究生。;通信作者：朋改非（1966-），男，博士，教授。
