146 / 2022-04-29 13:08:10

Performance and characterization of seawater blended cement-based material incorporated with polycarboxylate superplasticizer

Seawater; Superplasticizer; Rheological properties; Hydration; Microstructure

Manufacturing concrete with seawater could mitigate the freshwater shortage with both economic and environmental benefits. However, the effect of superplasticizers in seawater blended cementitious materials on the performance and characterization, such as fresh properties and hydration, and hardened characteristics has not been systematically explored. In this study, the effects of two typical polycarboxylate superplasticizers (PCEs, including water-reducing and slump-retaining PCEs) on the rheological properties (plastic viscosity, yield stress, thixotropic area), hydration heat, hardened properties, and microstructure of the hydration products of the seawater blended cementitious materials, were investigated, and compared with those of conventional OPC. Experimental results indicate that the addition of PCEs has changed the rheological behavior of both the tap water and seawater mixed cement paste in terms of shearing-thinning and shear-thickening. Moreover, although the seawater increased the hydration heat of the specimen with both PCEs, the components of hydration products were not affected. Furthermore, in the presence of both PCEs, the compressive strength of the seawater cementitious material increased, and the microstructures were densified after blending with seawater.