Powder gradation effect on the fresh, mechanical, and early-age shrinkage properties of UHPC. (15th May 2023)

• Record Type: Journal Article
• Authors: Du, Yang; Zhang, Lifeng; Ruan, Shaoqin; Qian, Xiaoqian; Qian, Kuangliang; Cheng, Pengyun; Lin, Gaohang
• Is Part Of: Journal of building engineering. Volume 67(2023)
• Publication Date: 2023-05-15
• Subjects: UHPC -- Silica fume -- Gradation effects -- Early-age shrinkage -- Hydration degree; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2023.105958
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: Particle sizes and proportions of powders (e.g., cement and mineral admixtures) may play an important role in determining the early-age performance of ultrahigh-performance concrete (UHPC). Therefore, in this study, the effects of powder gradation on the fresh state, mechanical properties, and early-age shrinkage of UHPC were investigated. The results show the effects of dense powder gradation on fluidity and early-age strength, which could be related to the variation of hydration processes. Moreover, considering the effect of the dry environment on the autogenous shrinkage, accurate assessments of the shrinkage components were available, which further revealed that drying shrinkage may dominate the total shrinkage of UHPC at an early age. Besides, as the evaporation was combined with the pore structure, the critical pore diameters were calculated and employed to theoretically clarify the development of drying shrinkage. Highlights: Performances of UHPC with good powder gradation were evaluated. Effects of positive gradation on its fluidity and early-age strength were seen. Development of autogenous shrinkage of UHPC under drying conditions. Drying shrinkage may dominate total shrinkage of UHPC in some cases. Mesopores proportion and evaporation in UHPC explained shrinkage profiles.