Fly Ash Concrete Specimens Admixed with Nanoparticles and Their Interaction with Seawater

This study is on fly ash (FA) concrete admixed with TiO2 nanoparticles (FAT), CaCO3 nanoparticles (FAC), and an equal ratio of TiO2 and CaCO3 nanoparticles (FATC) were exposed to seawater for 365 days in order to find the attachment of macrofoulants on their surface. The pH reduction studies were carried out in order to determine concrete deterioration in seawater, the results showed that FA specimens had more pH reduction than FAT, FAC and FATC. Total viable count, epifluorescence microscopy and denaturing gradient gel electrophoresis (DGGE) analysis confirmed the intensity of bacterial attachment and its diversity on FA, FAT, FAC, and FATC specimens. A systematic and comparative analysis predicted the overall relationship in terms of the dominant bacterial species on the different fly ash concrete specimens. To determine the biodeterioration of the fly ash concrete specimens in seawater, we used thermography experiments to evaluate the regions affected by bacteria on mortar specimens and confirmed that FA and FAC had more degradation and that FAT and FATC were the least degraded. Laser Raman Spectroscopy was interesting to find the white micron-sized particles of sulphur on FAC, FAT, and FATC specimens after 365 days immersed in seawater. We used a confocal laser scanning microscope to estimate the thickness of biofilm growth on FAT (13.91 0.38 mm), FATC (21.64 0.22 mm), FAC (33.56 0.26 mm), and FA (43.36 0.10 mm) specimens. The results showed that FAT and FATC specimens were the superior specimens, with enhanced biofouling and biodeterioration resistance in a seawater environment.