Comparative Evaluation of Compressive Strength of Concrete Produced with Granite and Gravel as Coarse Aggregates
Mohammed O. Ganiyu
Department of Civil Engineering, University of port Harcourt, Port Harcourt, Nigeria.
Udeh Israel Eyu *
Department of Civil Engineering, University of port Harcourt, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This study evaluated the influence of coarse aggregate type on the compressive strength of concrete, with particular emphasis on granite and locally sourced gravel. Concrete performance is largely governed by the properties of its constituent materials, among which coarse aggregates play a dominant role because of their contribution to strength, durability, and structural integrity. The investigation aimed to determine the suitability and performance differences between granite and gravel when used in conventional concrete production. A controlled laboratory experiment was conducted using two standard mix ratios of 1:2:4 and 1:3:6, prepared using the absolute weight-batching method. Preliminary material characterisation tests were carried out, including sieve analysis for aggregate grading, cement consistency and setting-time tests, and slump tests to evaluate workability. A total of forty (40) concrete cubes measuring 150 mm × 150 mm × 150 mm were cast, comprising both test and control specimens. The specimens were cured under standard water-curing conditions and tested for compressive strength at curing ages of 7, 14, and 28 days. The results showed a progressive increase in compressive strength with curing age for all concrete mixes. Concrete produced with granite consistently exhibited higher compressive strength than concrete produced with gravel across all curing periods and mix ratios. At 28 days, the maximum compressive strength recorded for granite concrete at a mix ratio of 1:2:4 was 27.3 MPa, while gravel concrete achieved 24.2 MPa under the same conditions. Similarly, for the 1:3:6 mix, granite achieved 23.9 MPa, compared with 20.0 MPa for gravel. The findings indicated that aggregate type significantly influences concrete strength, with granite providing better interlocking properties and reduced void content due to its angular shape and surface texture. However, gravel demonstrated acceptable strength performance and may be considered a viable alternative in situations where granite is unavailable or cost-prohibitive. The study concluded that, while both aggregates are suitable for concrete production, granite remains the preferred choice for structural applications requiring higher strength. The results provide practical insights for engineers and construction professionals in material selection and mix-design optimisation, contributing to improved construction efficiency and cost management.
Keywords: Concrete, compressive strength, coarse aggregate, granite, gravel, structural performance