Study on the deterioration of mortar by enteromorpha-diatoms during green tide

Similar to the deterioration of construction materials by airborne algae, hydrophytic algae can deteriorate cementitious materials and change the performance of structures, thereby reducing the safety and economics of marine facilities. Frequent outbreaks of green tides have occurred in recent years, and algae have been shown to deteriorate calcium substances in cementitious materials. Therefore, the pattern of deterioration of cement by algae as a result of green tide outbreaks is important for extending the durability of marine installations. For this reason, the dominant species of the green tide outbreak, Enteromorpha, and the marine primary producer, diatoms, were selected to simulate the green tide outbreak in this paper. Then, in the paper, the colonization law of Enteromorpha and diatom and the calcium loss law in mortar are discussed. Results showed four stages of Enteromorpha-diatoms colonization on the mortar surface (diatoms colonization within 15 days, release of spores from Enteromorpha, germination of spores from Enteromorpha within 60 days, and transformation of the relationship between the colonization of Enteromorpha and diatoms). Three channels for the loss of calcium on the surface of the mortar include the uptake and transformation, the complexation of biofilm, and the dissolution and deposition. Additionally, Enteromorpha-diatoms can deteriorate the mortar surface, mineral composition, and microstructure.