Effect of macro algae Ulva fasciata on concrete structures

Abstract

Ulva fasciata is a common chlorophyceae found on all coastal structure. Puducherry, India is a coastal region in Bay of Bengal where the growth of U. fasciata (Delile) is very abundant on all marine structures. Though, it causes secondary deterioration, its significance is often underestimated. To know its effect, the basic mechanism by which U. fasciata deteriorates concrete structures has been highlighted. To ascertain the detrimental effect by marine algae, U. fasciata on coastal concrete structures, M20 grade concrete cubes were casted and kept in the coastal area where there is abundant growth of U. fasciata and also laboratory simulation has been carried out. To examine the extent of deterioration done by U. fasciata on concrete surface, samples were collected from the M20 grade concrete cubes kept in the coastal area and simulated one. The collected samples were analyzed by SEM, EDX XRD TG and FTIR to establish the degree of deterioration done by marine algae on concrete surface. The result showed that there is sustainable effect by the marine algae on the concrete surface.

Biological Activities on Geopolymeric and Ordinary Concretes

“…This is caused by species such as Chaetomorpha antennina or Ulva fasciata, which can decompose and digest concrete to extract calcium or other substances. Ulva fasciata could completely remove calcium and alumina from concrete under laboratory conditions, while Chaetomorpha antennina removed some crystalline phases such as portlandite (calcium hydroxide) [25,26] (Figure 4).…”