Mechanism of strength evolution of seawater OPC pastes

Yangyang Zhang, Yanjie Sun, Haibing Zheng, Yamei Cai, Wing Lun Lam, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

This work investigated the strength degradation mechanisms of seawater ordinary Portland cement (OPC) pastes. Two types of specimens were prepared ((i) OSD sample (i.e. OPC was mixed with seawater, and then cured in deionized (DI) water) and (ii) ODD sample (i.e. OPC was mixed with DI water, and then cured in DI water, as the reference system)). The use of seawater in preparing OPC pastes effectively increased the hydration rate and early-age mechanical strength, but lowered the mechanical strength at the later age. The higher hydration degree and larger amounts of carbonates with a smaller crystal size enabled the seawater OPC pastes to exhibit a higher early-age mechanical strength, increasing by 13.0%–17.0% compared with the DI water OPC pastes. While the formation of Friedel’s salt and the formation of calcium-silicate-hydrate (C-S-H) gel with a lower polymerization degree and mean molecular chain length resulted in the deterioration of the pore structure and negatively affected the later-age strength development of the seawater OPC paste, decreasing by 5.8%–11.9% compared with the DI water OPC pastes.

Original languageEnglish
Pages (from-to)1256-1266
Number of pages11
JournalAdvances in Structural Engineering
Volume24
Issue number6
DOIs
Publication statusPublished - Apr 2021

Keywords

  • Cement
  • compressive strength
  • hydration products
  • microstructure
  • seawater

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction

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