ABSTRACT

This study investigated microorganism on concrete surface (old and new). The study was guided by three objectives, to identify the microorganisms, present on old and new concrete surfaces, to access the level of biodeterioration on concrete surface s and to determine the effect of microorganisms on concrete in the study area. Concrete samples were collected from Umuahia municipality area. A total of ten concrete samples were collected from lintel, gutter, floor, wall and painted pillar surface, for each type of surface old and new samples were collected using sterile chisel. Using spread plate techniques, they were cultured, isolated and characterized using morphological characteristic, pigmentation on media, microscopy and biochemical method. It was found that bacteria and fungi are the major microorganism found on concrete surface. The bacteria isolated revealed includes, Escherichia coli, staphylococcus aureus, Pseudomonas aeroginosa. Bacillus subtilis, Proteus species and Serratia species, while the fungal isolates revealed includes Mucor alternaria, Aspergillus flavus, Rhodotorula species and Aspergillus fimugatus. The total microbial counts in this study revealed that for bacteria, the surface sample with the highest count is old lintel surface sample at 4.7 x106 while the lowest is surface sample from gutter at 1.4x106. while for fungal the highest count was recorded in new painted pillar at 4.8x106 while the lowest is from old gutter surface at 2.5x106. This study recorded the same species of bacteria (6) and fungi (4) in both new and old surface, but varies in the mean count. Statistical analysis showed that there was significant difference in mean microbial count of concrete surface at P < 0.05. This study therefore concludes that microorganism initiates and intensifies concrete biodegradation.

TABLE OF CONTENTS

Cover Page

Title Page ii

Certiication

Dedication iv

Acknowledgement v

Table of Contents vi

List of Tables viii

Abstract x

CHAPTER ONE

1.0 INTRODUCTION                                                                                                      1

1.1 Aims and Objectives of Study 7

CHAPTER TWO

2.0 REVIEW OF RELATED LITERATURE

2.1 Microbial Colonization on Concrete 8 

2.2 Microbial Succession on Concrete 9

2.3 Microbial Deterioration Mechanism and Process 10 

2.4 Measures against Concrete Biodegradation 12

2.5 Influence of Microbes on Various Properties of Concrete 14

2.6 More Studies on Concrete 15

CHAPTER THREE

3.0 MATERIALS AND METHODS

3.1 Study Area 18

3.2 Sample Collection 18 

3.3 Sterilization of Culture Media and Other Materials 19

3.4 Procedure for Culturing 19 

3.5 Isolation of Microorganism 20

3.6 Identification of Bacterial Isolates 20

3.7 Statistical Analysis 23

CHAPTER FOUR

4.0 RESULT 25

CHAPTER FIVE

5.0 DISCUSSION, CONCLUSION AND RECOMMENDATION

5.1 Discussion 33

5.2 Conclusion 34

5.3 Recommendation 35

References

Appendix I

Appendix II

LIST OF TABLES

S/N TITLE PAGE

Table 1: Effect of the anaerobic microorganism’s addition on mortar strength       14

Table 2: Microbial Count       28

Table 3: Identification and Characteristics of Bacteria Isolates from Concrete Surface   29

Table 4: Identification and Characteristics of Fungi Isolates from Concrete Surface       30

Table 5: Isolates Occurrence from New Concrete Surface Samples       31

Table 6: Isolates Occurrence from Old Concrete Surface Sample       32