ABSTRACT

A study was conducted at Michael Okpara University Agriculture Umudike to determine the effect of water impurity, with sulphate being the impurity under study, on the compressive strength of concrete. Mix waters were appropriately sampled and the water was analyzed qualitatively and quantitatively in the laboratory to determine its physical and chemical parameters before using it to mix the concrete. Magnesium sulphate salt which was introduced as impurity at various level of 50g, 100g, I 50g and 200g by weighing each oft he grammes of the salt appropriately and introducing it into a 1000dm' water tank and properly m ' ixed by stirring vigorously. The water from the tank was then collected for concrete mixing. This was to determine the level at which the sulphate introduced will begin to affect the compressive strength of concrete. Clay and silt in sand was determined by sieve analysis to be 2 percent. A concrete mix of I :2:4(cement. sand, and stone ratio) was prepared with each water sample at their various impurity level of 50g, 100g. 150g and 200g; from which 40 cubes of concrete were cast in well oiled I 50mm steel moulds. Compressive strengths of the concrete cubes at ages of 3 days. 7days, I 4 days and 28 days of curing was determined. Result shows· that mix water that did not contain magnesium sulphate had no effect on the compressive strength of the cubes. Water at, various level of impurity was observed to adversely affect the compressive strength of cubes casted using such mix wc:ters. Qua[itative and quantitative analysis was conducted to ascertain the suitability of mixed water based on BS 3148 (1980) recommended for Ca', K', Mg, SO4 and HCO3 on mixing water.

TABLE OF CONTENTS

Pages

II

Title page

iii

Declaration

iv

Certification

V

Abstract

Vl

Dedication

Acknowledgement

vii Table of contents

X List of figures

XI·

List of tables

CHAPTER ONE- INTRODUCTION

I I-BACKGROUND OF TI-IE STUDY

1.2- STATEMENT OF THE RESEARCH PROBLEM

1.3- OBJECTIVES OF THE STUDY

1.4- SCOPE AND LIMITATIONS OF THE STUDY

1.5- JUSTIFICATION

CHAPTER TWO- LITERATURE REVIEW

2.1- CONCRETE

2.1.1- CLASSIFICATION OF CONCRETE

2.1.2- PROPERTIES OF CONCRETE

2.1.3- GRADES OF CONCRETE

2.1.4- ADV ANT AGES AND DISADVANTAGES OF CONCRETE

2.2- CEMENT AS CONCRETE MAKING MATERIAL

2.3-' AGGREGATE AS CONCRETE MAKING MATERIAL

2.4. WATER AS CONCRTETE MAKING MATERIAL

2.4.1 QUALITY OF MIXING WATER

2.5 COMPRESSIVE STRENGTH OF CONCRETE

2.5.1 STRENGTH AND DEFORMATION OF CONCRETE IN COMPRESSION 113 2

25.2 RELATIONS BETWEEN COMPRESSIVE STRENGTH, TENS;;

STRENGTH AND MODULUS RUPTURE 14

?5.3- WATER CEMENT RATIO AND COMPRESSIVE STRENG7,,,

2.6- EFFECT OF IMPURITIES IN WATER ON COMPRESSIVE STRENGTH ,}

CONCRETE (DISSOLVED SALTS IN WAT,,,

2.7 SULPHATE A TT ACK ON CONCRETE . 18

. VI)

2.8- EFFECT OF OTHER IMPURITIES ON COMPRESSIVE

STRENGTH OF CONCRETE

2.8.1- EFFECT OF BIOCARBONATE ON COMPRESSIVE

STRENGTH OF CONCRETE

2.8.2- EFFECT OF CHLORIDE ON COMPRESSIVE STRENGTH OF CONCRETE

2.8.3- EFFECT OF ALKALINE ON COMPRESSIVE STRENGTH OF CONCRETE

2.9- RESONS FOR STUDYING EFFECT OF SULPHATE ON

COMPRESSIVE STRENGTH OF CONCRETE

CHAPTER THREE- MATERIALS AND METHODS

3.1- LABORATORY DETERMINATION OF PHYSICAL

PARAMETER OF SAMPLE WATER USED 22

3.1.1- DETERMINATION OF PH VALUE 22

3.1.2- DETERMINATION OF COLOUR 22

3.1.3- DETERMINATION OF TEMPERATURE 22

3.1.4- DETERMINATION OF TRUBIDITY 22

•

3.1.5- DETERMINATION OF TOTAL DISOL YEO SOLID AND CONDUTIVITY 22

3.2- LABORATORY DETERMINATION OF CHEMICAL

PARAMETER OF SAMPLE WATER USED

3.2.1- DETERMINATION OF MAGNESIUM (Mg')

3.2.2- DETERMINATION OF SULPHATE (SO/)

3.2.3- DETERMINATION OF CALSSIUM (Ca?')

3.2.4- DETERMINATION OF POTASSIUM (K')

3.2.5- DETERMINATION OF SODIUM (Na')

.

3.2.6- DETERMINATION OF NITRATE (NO,)

3.2.7- DETERMINATION OF PHOSPHORUS (PO)

3.2.8- DETERMINATION OF BICARBONATE (CO/HCO,)

3.2.9- DETERMINATION OF AMMONIA (NH)

3.2.10- DETERMINATION OF CHLORINE (CL)

3.2. I 1- DETERMINATION OF NITROGEN (N)

3.2.12- DETERMINATION OF LEAD (P")

3.2.13- DETERMINATION OF IRON (Fe')

3.3- LABORATORY DETERMINATION OF SILT AND CLAY CONTENT OF

FINE AGGREGATE USED (SIEVE ANALYSIS)

3.4- CUBES PREPARATION AND CURING

3.5-COMPRESSIVE STRENGTH TESTING OF CUBES

(CRUSHING TEST OF CUBES)

CHAPTER FOUR

4.0- RESULTS AND DISCUSSIONS·

CHAPTER FIVE

5.0- CONCLUSION AND RECOMMENDATIONS

5.1- CONCLUSION

5.2- RECOMMENDATIONS

REFERENCES

LIST OF TABLES

Pages

Table 2.1- Grades of Concretes; Indian Standard (IS: 456 -2000). 8

Table 2.2- Strength of Concrete with number of Days of Curing. 12

Table 2.3- Effect of Dissolved Salts in Water on Compressive Strength of Concrete. 17

Table 2.4- Requirement of (ACI: 318) American Concrete Institute for Concrete

I

Exposed to Sulphate attack 19

Table 4.1- Laboratory Determination of silt and Clay content of fine

Aggregate used (Sieve Analysis Result). 30

Table 4.2- Result of Physical and Chemical Analysis of Sample water Used. 32

Table 4.3- Weight of Concrete Cubes in kg before crushing. 33

Table 4.4- Mean Compressive Strength and Rates of Strength Gain by Concrete Cubes. 34

LIST OF FIGURES

Figure 2.1- Effects of Age on Compressive Strength.

Figure 2.2- Typical Concrete Stress-Strain Curves.

Figure 2.3- Relations between Compressive Strength, Tensile Strength and

Modulus of Rupture

Pages

Figure 2.4- Effects of Water-Cement Ratio on Compressive Strength at Different Ages. 16

Figure 4.1- Particle size Distribution· of fine Aggregates. 31

' Figure 4.2- Variation of Compressive Strength with Age for different Sample Water. 35