A new approach to investigate the hydration process and the effect of algae powder on the strength properties of cement paste

Sargassum muticum, a Japanese brown seaweed, has recently invaded various shorelines throughout the world, including the Atlantic coast of Morocco, where it has developed significant populations. We report on the use of these algae as a partial replacement of Portland cement in cement paste as part of a long-term plan to combat this invasive seaweed. With a fixed water to cement ratio (W/C = 0.45), algae powder is added at 5%, 10%, 15% and 20% from the cement content in producing cement pastes. The hydration process was assessed using impedance spectroscopy throughout the setting period from 10 min to 28 days. Compressive strength tests were performed at 7, 14 and 28 days. An equivalent circuit model has been proposed. The results showed that the various strength properties of the cement paste increased or decreased with addition of algae powder. The compressive strength tends to increase with the addition of algae powder. This study shows that 10% addition of algae powder to cement paste showed an increase in compressive strength and when the addition increased to 20% the properties started to decrease.