ALGAE GROWTH ON CONCRETE SURFACES OF BUILDINGS IN SINGAPORE

Abstract

Algae growth on concrete disfigures the external surfaces of buildings and can cause bio-deterioration to the building material. Algae growth is further accelerated in a humid country like Singapore, where many concrete surfaces of buildings are susceptible and affected by algae stains. Hence, the main objective of this dissertation is to search for a potential cost-saving alternative to minimize algae attacks.

Algicidal paints are adopted for use on surfaces to prevent the growth of algae due to exposure to the uncontrollable harsh elements of weather. However, paints, no matter how strong they are bonded to the substrate, will peel off eventually. In general, what is left unprotected and vulnerable to algae attack is the plaster layer of the concrete surface.

It is hypothesized and tested by an experiment that algicide added and mixed with cement-sand plaster mixture can effectively prevent algae growth and when used together with algicidal paint, this combination will be able to act as a double protection should the paint peels off.

The result of the experiment shows that 1.0% of algicide added to the plaster mixture has achieved a surface with no algae growth and when both algicidal paint and algicidal plaster are used, the surface is clear of algae stains. This reveals that algicidal plaster is effective to a certain extent in preventing algae growth and with the dual system of algicidal paint and algicidal plaster; it acts as reinforcement in preventing algae growth.

Limitations identified are mainly due to time constraint and only one type of algicide/algicidal paint is used.