Understanding the time-dependent rheological behavior of seawater mixed cement paste with fly ash

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Meng Zhang
  • Wenkai Shen
  • Zuquan Jin
  • Shaochun Li
  • Weijun Gao

Detail(s)

Original languageEnglish
Article number138910
Journal / PublicationConstruction and Building Materials
Volume451
Online published26 Oct 2024
Publication statusPublished - 15 Nov 2024

Abstract

Due to the relative scarcity of freshwater resources in coastal regions, the use of seawater in concrete construction has great potential due to its benefits in cost and resource. To further advance the application of seawater concrete, a deeper understanding of its rheological properties is essential. This study investigates the effects of fly ash on the time-dependent rheological behavior of seawater cementitious paste, such as yield stress, plastic viscosity, and structural build-up rate. The underlying mechanisms are analyzed using the theories of water film thickness (WFT), ion concentration, and hydration heat. The research findings confirm that the rheological parameters of seawater paste are generally higher than those of deionized water paste, regardless of the cementitious compositions. As fly ash content increases, the plastic viscosity of seawater paste increase, while the fluidity and dynamic yield stress decreases. Further analysis reveals that the decrease in the yield stress with fly ash content is well related to the increase in the WFT, but it cannot sufficiently explain the change of yield stress over time. Instead, the amount of hydration products in seawater paste shows a linear increasing relationship with the dynamic yield stress at 65 min. By contrast, the plastic viscosity can be related to the ion concentration in the interstitial solution, wherein an increase in the concentration of Ca2+ corresponds to an increase in the plastic viscosity. Moreover, the rheological parameters increase over time, with the growth rates between 5 and 35 minutes being higher than those between 35 and 65 minutes, possibly due to the rapid early hydration of the binder materials. This study offers a fundamental theoretical support for the use of seawater in various concrete applications. © 2024 Elsevier Ltd.

Research Area(s)

  • Seawater, Rheological properties, Fly ash, Ion concentration, Water film thickness

Citation Format(s)

Understanding the time-dependent rheological behavior of seawater mixed cement paste with fly ash. / Zhang, Meng; Shen, Wenkai; Jin, Zuquan et al.
In: Construction and Building Materials, Vol. 451, 138910, 15.11.2024.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review