An Appraisal of the Variation in the Physico– mechanical Properties of Granitic Aggregates: Focus on Some Quarry Sites in Ogun State, Nigeria

Coarse aggregate is an essential constituent of concrete constituting about 60% to 80% of concrete
depending on the mix ratio. Granite is reported to be the most widely distributed plutonic rock in the
earth crust. It is predominantly available in various parts of Ogun State of Nigeria. Its different
properties have been known to strongly influence the fresh and hardened state properties of concrete.
In this study, samples of four different sizes of granites (9.5 mm, 12.5 mm, 19 mm and 25 mm) were
obtained from four different quarry sites across the state. Sieve analysis was carried out on samples
from all the locations while the physical properties such as specific gravity, moisture content and
water absorption and the Mechanical properties such as aggregate impact value and aggregate
crushing value of the samples were evaluated. The result of the sieve analysis reveals that there are
variations in the gradations of samples from the various locations. The results of the specific gravity,
moisture content and water absorption vary from 2.61 to 2.86, 0.69 to 1.22%, 0.16 to 2.13%
respectively. While the aggregate impact value and aggregate crushing value vary from 18.30 to
28.12% and 6.21 to 9.45% respectively. It was therefore concluded that there are variations in the
physical and mechanical properties of granites produced in Ogun State of Nigeria. The observed
variations occur in relation to the various sizes and for the different quarry sites.