INFLUENCE OF MORTARS CHEMICAL COMPOSITION ON ALGAL BIOFOULING

SUMMARY: The main cause of building-facade biodeterioration is the growth of microorganisms. The state of surface is a mong parameters which affects the most biofouling kinetics. The main obje ctive of this study is to highlight the influence of mortar chemistry and its physical properties on algal growth. The green algae Klebsormidium flaccidum has been chosen for this work because of its representativeness. In ord er to characterize the influence of the mortar chemistry on biofouling, Po rtland cement (CEMI) and aluminate cement (CAC) were used. The biofouling kinetics was followed on samples tested in a laboratory bench, w here the mortar specimens were exposed to a sprinkling of algal sus pension. The algal growth was daily monitored by image analysis. The colonization rate was given by the ratio of colonized area to the total s urface. In our case, the surface roughness doesn’t seem to affect the algal colonization. The experimental method highlights that surface pH and chemistry of cement used in mortar formulations have an influence on al gal fouling. In fact, the colonization kinetics of CAC mortars is lower than that of CEMI mortars.