ASSESSMENT OF CONCRETE AGGREGATES IN IBADAN, NIGERIA BY AJAGBE W. O. and TIJANI, M. A.* Department of Civil Engineering, Faculty of Technology, University of Ibadan, Nigeria. *E-mail: murikilekun@gmail.com

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.

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

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.

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

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

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

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

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% IS383-1970 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

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)

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 1120-1920 Specific Gravity 2.64 2.57 2.61 2.59 2.62 2.60 2.56 2.54 2.4-3.0 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

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.

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.

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.

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.

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