Mix Design and Proportioning

Materials

Preparation of Cylindrical Mortar Specimens

Preparation of Microbial Culture Media

MAB Culture Media

SRB Culture Media

Post Exposure Analysis

X-Ray Diffraction Studies

Visualization of the Surfaces

Degradation Parameters in Microbial Cultures

Biofilm Characterization Studies in Bacterial Cultures

Epifluorescence Microscopic Analysis

Confocal Laser Scanning Microscopy Analysis

XRD Analysis

DISCUSSION

CONCLUSIONS

LITERATURE CITED

INTRODUCTION

Nuclear structures are generally designed with a service life of about 40 years. The present interest is to extend their life span over 60–۱۰۰ years, using the new technologies, in order to reduce the cost per unit power production. There are many concrete structures associated with a power plant, for example, cooling water system, intake pipes, etc., which are exposed to harsh and aggressive marine environments, either directly or indirectly. The structural stability of concrete structures in contact with seawater is of extreme importance for the long term service of a nuclear industry [1–۳]. Concrete structures are severely affected by factors like carbonation, ingression of chloride and sulfate ions, microbial corrosion, etc. The corrosion due to acid producing microbes takes place through the formation of active biofilms on the concrete surface [4]. Among various factors affecting the deterioration of concrete structures, the one due to biological origin is very significant in aggressive environments due to the production of biogenic corrosive substances by the microorganisms [5,6]. Microorganisms form colonies over the surface of concrete and results in the structural, functional, and aesthetic damage of concrete structures [7]. Microbial growth over concrete surfaces can take place under a wide range of environments like elevated humidity, prolonged freezing and thawing, high levels of carbon dioxide or chloride ingress, high concentrations of sulfates, and very small amount of acids [8]. The scope of improving the durability and performance of concrete through incorporation of mineral and chemical admixtures paved the way to development of a class of concrete called high performance concrete (HPC) with a reduced water to cement (w/c) ratio and enhanced properties. There are many pozzolanic materials like burning rice husk, blast furnace slag, fly ash, etc. that can replace cement in the production of concrete. But CO2 emissions from burning rice husk also form a part of the global carbon cycle [9]. Thus, the need of the hour is to reduce the emission of CO2 in the construction industry through the application of sustainable techniques and technologies [10]. Among the most commonly used mineral admixtures, fly ash, a waste product from coal based power plants, is incorporated in concrete in order to reduce the utilization of cement and to improve its durability, thereby making it an environment friendly green concrete. Despite these advantages, there are some early-age performance issues reported for fly ash concrete like low early-age strength, high calcium leaching, etc. [11,12].