COMPARATIVE ANALYSIS OF THE STRENGTH OF CONCRETE MADE FROM VARIOUS AGGREGATES

ABSTRACT The Nigerian construction industry heavy relies on concrete. One of the major constituents of concrete is aggregate. Having option of selecting locally available aggregates could help to reduce the cost of producing concrete. The study compares the strength of concrete made from various aggregates (granite, river gravel, reused concrete aggregate and burnt brick) The concrete grade 25 and 30 was adopted for the mix with a constant free water to cement ratio of 0.58. Five cubes and cylinders were produced at each aggregate used (granite, river gravel, reused concrete aggregate and burnt brick) for the two grades of concrete. The mould dimension for cubes and cylinder was 150 mm and 150 x 300 mm. Results from various tests highlight notable differences in performance. The sieve analysis reveals coefficients of uniformity (2.25) and curvature (1.00) for river sand, indicating its grading quality. Water absorption varies significantly, with granite concrete showing the lowest (6-8%), river gravel moderate (6-7%), burnt brick the highest (11-13%), and reused aggregates at 10-12%. Slump tests show granite with moderate workability (50-54 mm), river gravel slightly variable (47-53 mm), burnt brick the least workable (29-36 mm), and reused aggregates in a mid-range (40-45 mm). Density measurements position granite concrete as the densest (2519 kg/m³), followed by river gravel (2400-2504 kg/m³), reused concrete (2222 kg/m³), and burnt brick (1985-2504 kg/m³). Compressive strength demonstrates granite as the strongest (20.13-29.39 N/mm²), river gravel comparable, burnt brick the weakest (5.95-8.18 N/mm²), and reused aggregates intermediate (21.28-23 N/mm²). Split tensile strength follows a similar trend, with granite achieving the highest (2.47-4.16 N/mm²), river gravel slightly lower, burnt brick the least (0.33-1.10 N/mm²), and reused aggregates offering sustainable yet moderate performance (2.11-3.32 N/mm²). Granite consistently outperforms due to its superior mechanical properties, while reused aggregates provide a viable, eco-friendly alternative with acceptable performance for sustainable construction practices.