Zuo Zhiwu, Zhang Jiachen, Li Beixing, Shen Chuqi, Xin Gongfeng, Chen Xiao
Shandong Key Laboratory of Highway Technology and Safety Assessment, Jinan 250000, China.
Shandong Hi-Speed Group Co., Ltd., Jinan 250000, China.
Materials (Basel). 2022 Feb 23;15(5):1668. doi: 10.3390/ma15051668.
This paper investigates the effect of curing regimes (standard and steam curing) on the mechanical strength, hydration, and microstructure of ecological ultrahigh-performance concrete (EUHPC). The flowability, compressive strength, flexural strength, hydration, porosity, pore size distribution, and microstructure of UHPC with different contents of supplementary materials (silica fume, fly ash, and ground granulated blast furnace slag) were assessed. The test results showed that the compressive strength of EUHPC under steam curing was increased considerably compared to that under standard curing, while the flexural strength was mildly decreased. The steam curing could decrease the porosity of EUHPC, which ranged between 7% and 9% for standard curing, and between 3.5% and 5% for steam curing. The aperture of EUHPC was below 20 nm, mainly located in the range of 10 nm to 20 nm under standard curing, while it was less than 10 nm for steam curing. C-S-H gel was produced under steam curing, while unhydrated fly ash, mineral powder, and Ca(OH) crystal were observed in the amorphous C-S-H gel. The microstructure of EUHPC under steam curing was denser than that under standard curing, and the interfacial transition zones under both curing regimes were compact.
本文研究了养护制度(标准养护和蒸汽养护)对生态超高性能混凝土(EUHPC)力学强度、水化和微观结构的影响。评估了不同掺合料(硅灰、粉煤灰和磨细粒化高炉矿渣)含量的超高性能混凝土(UHPC)的流动性、抗压强度、抗折强度、水化、孔隙率、孔径分布和微观结构。试验结果表明,与标准养护相比,蒸汽养护下EUHPC的抗压强度显著提高,而抗折强度略有降低。蒸汽养护可降低EUHPC的孔隙率,标准养护下孔隙率在7%至9%之间,蒸汽养护下孔隙率在3.5%至5%之间。EUHPC的孔径小于20nm,标准养护下主要位于10nm至20nm范围内,而蒸汽养护下小于10nm。蒸汽养护下生成了C-S-H凝胶,在无定形C-S-H凝胶中观察到未水化的粉煤灰、矿粉和Ca(OH)晶体。蒸汽养护下EUHPC的微观结构比标准养护下更致密,两种养护制度下的界面过渡区都很致密。