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Abstract
An experimental investigation on the chemical, physical, mechanical, and shrinkage of seawater and sea sand-based ultra-high-performance concrete (UHP-SWSSC) with supplementary cementitious materials (SCM) (i.e. slag and silica fume) is reported. Several mixes were designed with varying proportions of SCMs (25%, 37.5%, 50%, and 62.5% of binder), aggregate source, and water-to-binder ratio. Heat evolution, density, workability, compressive strength development, and long-term autogenous and drying shrinkage of UHP-SWSSC were monitored. Seawater accelerates cement hydration as reflected in the heat evolution, and consequently, dictates the early-age strength, and autogenous shrinkage. SCM addition although limits the early-age strength development offers a comparable 90 days strength. The chloride content increases from marine resources and may limit the application to nonstructural components. Nonetheless, a UHP-SWSSC mix with 50% OPC replaced by 37.5% slag and 12.5% silica fume is recommended in this study, which can achieve satisfactory workability, long-term strength, and shrinkage properties.
Acknowledgments
The authors wish to acknowledge Randwick Council for their permission to collect seawater and sea sand from Malabar beach in Sydney, NSW. We thank Mr. William Terry and Mr. Luiz Pettersen, technical staff of the Infrastructure Laboratory at UNSW for their assistance in the preparation of specimens. Finally, the authors also acknowledge the use of facilities within the Mark Wainwright Analytical Centre at UNSW for X-ray fluorescence spectroscopy and scanning electron microscopy.
Disclosure statement
No potential conflict of interest was reported by the authors.