Exploring the impact of coarse aggregate type on the mechanical performance of concrete mixtures

This study investigates the influence of coarse aggregate type granite, limestone, and quartz on the fresh and mechanical properties of C20 concrete. Concrete mixes were evaluated for workability, water absorption, compressive strength, and flexural strength at 7 and 28 days of curing, with results reported as mean ± standard deviation (SD) from triplicate specimens. Slump tests indicated low workability, with mean values of 30 ± 2 mm, 50 ± 3 mm, and 45 ± 2 mm for granite, limestone, and quartz, respectively, reflecting differences in aggregate texture and angularity. Water absorption at 28 days was lowest for granite (0.9 ± 0.05%), followed by limestone (1.3 ± 0.07%) and quartz (2.1 ± 0.09%), indicating variation in density and aggregate–paste bonding. Compressive strength at 28 days reached 20.1 ± 0.8 MPa (granite), 19.3 ± 0.7 MPa (limestone), and 18.1 ± 0.9 MPa (quartz), while flexural strength ranged from 4.15 ± 0.15 MPa to 3.16 ± 0.13 MPa, following a similar trend. ANOVA confirmed statistically significant differences between granite and quartz mixes (p < 0.05), supporting the reliability of the findings. The results demonstrate that granite aggregates provide superior strength and durability, limestone offers moderate performance, and quartz is suitable for general structural use. The study underscores the critical role of aggregate selection and recommends future work on admixture optimization, hybrid aggregate blends, and long-term durability evaluation.