Studies on Biodegradation of normal concrete surfaces by fungus Fusarium sp.

Abstract

The main objective of this study was to identify the potential of different concrete deteriorating acid producing microbes for removing surface layers of contaminated concrete structures. Studies were made using an acid producing fungus, Fusarium sp in a humidity chamber for one year and compared the degradation with the Thiobacillus sp. The growth of fungus as a black biofilm on the normal concrete surface in the humidity chamber was confirmed by culture techniques even after one year. Results of degradation parameters showed higher pH reduction, weight loss and thickness loss under Fusarium sp. biofilms. Epifluorescence micrographs clearly confirmed dense growth of filamentous Fusarium sp. Laser Raman spectroscopic and XRD analysis showed weakening of calcium silicate bands and presence of calcium oxalate bands confirming biodegradation. Thus by thinning of the concrete specimen by 2.27mm in one year the potential of this species for cleaning contaminated concrete surfaces is demonstrated.