1. ASSESSMENT OF CONCRETE AGGREGATES IN IBADAN, NIGERIABY
AJAGBE W. O. and TIJANI, M. A.*
Department of Civil Engineering, Faculty of Technology,
University of Ibadan, Nigeria. *

2. Concrete = cement paste + aggregates
INTRODUCTION
Concrete = cement paste + aggregates
Properties of concrete in fresh and hardened state depend on properties of constituent materials
Hence, aggregates, both fine and coarse, which take about 65-75% by volume of concrete are important ingredients in concrete production
Selecting the right aggregate material for concrete production is vital to overcome the recurrent problem of concrete failure in collapsed buildings.

3. AIM OF THE STUDY
To assess some aggregates being quarried around Ibadan for use in concrete construction.

4. OBJECTIVES OF THE STUDY
To provide some geotechnical information about some aggregates being quarried around Ibadan
To provide mechanical, physical and chemical characterization of the aggregates obtained from the quarries.
To compare the examined engineering properties with the permissible limits of BS, IS and ASTM test methods.
To know and recommend quarries with acceptable aggregate materials for concrete production.

5. Questionnaire administration Sample collection Sample preparation
METHODOLOGY
Questionnaire administration
Sample collection
Sample preparation
Laboratory experiments

6. Eighteen quarries were selected for the study
METHODOLOGY
Eighteen quarries were selected for the study
Coarse Aggregate Sources
Express C1
Kopek C2
Ratcon C3
Platinum C4
Wetipp C5
Digital C6
Lord Chosen C7
Spring C8
Fine Aggregate Sources
Ogunpa F1
Iddo F2
Ajibode F3
Egbeda F4
Moniya F5
Ogunmakin F6
Ikire F7
Akinyele F8
Ona-Ara F9
Onigari F10

7. Coarse Aggregates Fine Aggregates
METHODOLOGY
Laboratory Tests on:
Coarse Aggregates Fine Aggregates
Grading
Relative Density
Water Absorption
Bulk Density
Materials Finer than 75microns
Flakiness Index
Elongation Index
Aggregate Impact Value (AIV)
Los Angeles Abrasion Value (LAAV)
Aggregate Crushing Value (ACV)
10% Fines Value
Particle Size Distribution
Bulk Density
Specific Gravity
Atterberg Limit
Sand Equivalent
Water Absorption
Clay Lumps And Friable Particles
Amount of Materials Passing 75µm
Organic Impurities

8. RESULTS Fig. 1: Particle Size Distribution Graph (Coarse Aggregates)
USCS Classification: Poorly graded gravel, gravel-sand mixtures, little or no fines

9. RESULTS
Table 1: Tests and permissible limits for engineering properties of coarse aggregates for concrete as stipulated by BS, IS, ASTM and other authorities
Test/Sample C1 C2 C3 C4 C5 C6 C7 C8
Permissible Limits
Authority
Relative Density
Oven-dry
SSD
Apparent
2.76
2.78
2.81
2.44
2.47
2.50
2.82
2.84
2.88
2.90
2.93
2.74
2.77
2.80
2.79
2.61
2.62
2.64
2.51
2.53
2.57 -
Min. 2.6
2.6 – 2.8
2.5 – 3.0
ASTM C33
Shetty (2005)
Neville (2011)
Water Absorption (%)
0.67
1.01
0.69
0.59
0.79
0.49
0.44
0.90
Max. 2%
Max. 3%
BS5337:1976
Bulk Density (Kg/m3)
1530
1541
1622
1663
1500
1605
1470
1591
1200–1750
Kosmatka et. al. (2003)
Voids (%)
44.56
36.89
42.55
42.36
45.25
42.24
43.68
36.65
30% - 45%
Materials Finer than 75microns (%)
0.3
0.2
0.1
0.4
BS882:1992
ASTM C33-03
Flakiness Index (%)
16.70
18.24
16.03
20.97
18.04
16.11
20.32
14.57
Max. 30%
Max. 40%
FMW, 1997
Elongation Index (%)
23.96
25.44
27.87
22.90
24.05
19.63
23.19
18.98
Aggregate Impact Value (%)
9.12
12.46
10.09
9.14
11.04
8.83
8.52
12.16
Max. 25% IS
Los Angeles Abrasion Value (%)
18.32
21.26
18.68
18.14
19.72
17.30
16.10
20.40
Aggregate Crushing Value (%)
19.7
21.9
20.3
19.9
20.8
19.4
18.4
21.7
Max. 45%
10% Fines (Dry) KN
286
246
273
279
269
291
300
261
Min.100KN

10. RESULTS Fig. 2: Particle Size Distribution Graph (Fine Aggregates)
USCS Classification:
Poorly graded sand: F1
Poorly graded sand with gravel: F5, F8
Poorly graded sand with silt: F3, F9
Well graded sand with silt: F4
Silty sand: F2, F6, F7, F10
Fig. 2: Particle Size Distribution Graph (Fine Aggregates)

11. RESULTS
Table 2: Tests and permissible limits for engineering properties of fine aggregates for concrete as stipulated by BS and ASTM standards
Test/Samples F1 F2 F3 F4 F5 F6 F7 F8 F9
F10
Limits
Bulk Density (Kg/m3)
1590
1660
1600
1570
1550
1620
1440
1470
Specific Gravity
2.64
2.57
2.61
2.59
2.62
2.60
2.56
2.54
Aterberg Limit LL PL PI NP 17 14 15 -
Sand Equivalent(%) 81 38 67 59 86 34 50 77 37 31
Min. 30%
Water Absorption(%)
0.7
0.8
1.2
1.3
1.7
1.8
2.0
2.6
Max. 2%
Clay Lumps & Friable Particles (%)
0.40
1.33
0.32
0.96
0.70
1.34
1.99
0.16
5.96
0.18
Max. 3%
Matrerials Finer than 75microns (%)
0.62
20.09
4.88
10.77
2.76
12.81
13.82
1.95
11.78
13.83
Max. 5%
Organic Impurities
Not Present
Present

12. F10 had water absorption of 2.6% which exceeded maximum 2% specified.
DISCUSSION
The results revealed that coarse aggregates from all the eight quarries C1 - C8 complied with the requirements prescribed in BS and ASTM standards and thereby regarded as strong and durable for concrete construction.
Some fine aggregates were established to be sound and good as they fell within the limits of standard specifications while some were found to deviate from limit in certain respect.
F10 had water absorption of 2.6% which exceeded maximum 2% specified.

13. F2, F4 and F7 showed an indication of having organic impurities.
DISCUSSION
F9 was not free from clay lumps and friable particles with a significant value of 6% as against 3% maximum specification.
Samples F2, F4, F6, F7, F9 and F10 have more amounts of materials passing the 75µm sieve ranging from 10.8% for F4 to 20.1% for F2 than maximum of 5% in standard specification.
F2, F4 and F7 showed an indication of having organic impurities.

14. CONCLUSIONS
Coarse aggregate from all the quarries examined (C1 – C8) are generally strong and durable for concrete construction because of their possession of necessary characteristics when compared with BS, IS and ASTM standards.
Only fine aggregate from quarries F1, F3, F5 and F8 which complied fully with the requirement of the standards are sound and good.

15. RECOMMENDATIONS
It is recommended that performance test be conducted on concrete made from F2, F4, F6, F7, F9 and F10 to ascertain the level of interference of deleterious substances in them on chemical reaction of cement hydration, bond development between aggregate and cement paste as well as strength and durability of concrete before being used in concrete construction.

16. Thank you
for listening