Engineering Characterization of Rocks from the Minna Granitic Formation as Pavement Construction Aggregates

Rocks from the Minna granitic formation were assessed for their suitability as aggregates in pavement construction. Eight rock samples were collected and subjected to petrographic, mechanical (Aggregate Impact Value, Los Angeles Abrasion Value) and physical (Water Absorption, specific gravity) tests. Petrographic studies revealed that the study area is made up of fine and coarse grained granites as well as schist. The granitic rocks have specific gravity of 2.44 – 2.67 with water absorption of 2.57% and 3.17% while the schist has specific gravity of 2.21 and water absorption of 3.63%. The granites have mechanical properties of between 17.46% 20.89%, 19.40 21.00%, for Aggregate Impact Value and Los Angeles Abrasion Value respectively. The schist has aggregate impact value of 37.73% and Los Angeles Abrasion Value of 39.36. The results generally reveal that the aggregates derived from the granites are of fairly good engineering properties while that derived from the schist is considered as weak. The granite derived aggregates will produce pavements of fairly good quality while the schist should not be contemplated for the purpose of pavement construction.