摘要
研究了不同微波养护参数(输出功率和持续时间)及微波-干热组合养护对活性粉末混凝土(RPC)力学性能的影响,并采用X射线衍射、扫描电子显微镜和压汞法对二种养护下RPC的微观结构进行了分析.结果表明:微波养护可明显提高RPC砂浆的早期力学性能,并且适当延长微波持续时间有利于力学性能的提高;但随着RPC尺寸的增大,微波养护对其力学性能的提升效果会受到影响.采用微波-干热组合养护制度,可以克服单一微波养护的局限性,进一步提高RPC的力学性能.原因在于微波养护阶段RPC内部形成了致密的微观结构框架体系,这一结构体系在随后的干热养护中构建了一个近似于“蒸压釜”的高温蒸汽养护环境,进一步加速了水泥的水化及掺合料的火山灰反应,生成数量更多、结构更致密的水化产物,填充内部孔隙,优化孔结构.
The effects of microwave curing with different parameters(output power and duration)and the combined curing of microwave and dry air heating on the mechanical properties of reactive powder concrete(RPC)were studied.The microstructure of RPC under the two curing regimes was analyzed by X-ray diffraction,scanning electron microscopy and mercury intrusion porosimetry.The results indicate that microwave curing obviously improves the early mechanical properties of RPC,and appropriately prolonging the microwave duration is beneficial for further enhancing the mechanical properties.However,with the increase of RPC size,the improvement effect of microwave curing on mechanical properties will be affected.The limitation of single microwave curing can be overcome and the mechanical properties of RPC can be further improved by using the combined curing of microwave and dry air heating.The reason is that a dense microstructure framework system is formed inside the RPC during microwave curing stage,which builds a high-temperature steam curing environment similar to the"autoclaving"in the subsequent dry air heating.This environment further accelerates the hydration of cement and the pozzolanic activity of admixtures,which generates hydration products with more and denser structure to fill the internal pores and optimizes the pore structure as well.
作者
牛旭婧
许雍久
朱可欣
朋改非
NIU Xujing;XU Yongjiu;Zhu Kexin;PENG Gaifei(School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Faculty of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《华中科技大学学报(自然科学版)》
北大核心
2025年第8期51-58,共8页
Journal of Huazhong University of Science and Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(52378277,52008230,51878032,52130901)
北京市自然科学基金资助项目(8172036,8212013)
中央高校基本科研业务费专项资金资助项目(2023ZKPYLJ05).
关键词
活性粉末混凝土
微波养护
组合养护
力学性能
微观结构
reactive powder concrete
microwave curing
combined curing
mechanical properties
microstructure
