Abstract
The study aims to understand the strength, durability, and suitability of Abuja rock for planning, design, and construction of engineering projects. Three quarries in Abuja (Kubwa, Mpape, and Lugbe) were selected, and four samples were observed to be the most dominant, covering 90%-95% of the rock used in manufacturing aggregates for engineering construction. Geotechnical engineering properties of these rocks were analyzed in an engineering laboratory. Experimental tests included uniaxial compression test, Schmidt hammer rebound test, Los Angeles Abrasion test, Water absorption/moisture content test, and Specific gravity test. The compressive strength ranges from 21.32Mpa to 28.91Mpa, classified as sedimentary rock with moderate hardness. Schmidt rebound numbers range from 21.94 to 35.28, providing immediate access to rock strength. This shows on correlation with R²= 0.409 means the uniaxial compressive strength value is nearly proportional to the Schmidt rebound number. The specific gravity and water absorption relationship showed a negative correlation, with values of 2.43, 2.32, 2.32, and 2.28 on specific gravity and 0.15%, 0.22%, 0.20%, 0.17% on water absorption/water content from porphyritic granite, porphyroblastic gneiss, biotite granite, and granite gneiss, respectively. It shows in a correlation that water content is inversely proportional to the specific gravity with value of R²=0.400. Los Angeles abrasion values were within the allowable range (20-30) which reveals values from 21.00 to 23.00. The study reveals that the engineering characteristics of the sampled rocks are within the standard range for construction purposes. Porphyritic gneiss and granite gneiss are suitable for building and road construction due to their higher compressive strength and low water absorption, providing good strength and durability under different prevailing environmental conditions.

Key words: Geology , Rocks , Los Angeles Abrasion, Geotechnical