Recent Publications
Aggregate shape is an important factor for concrete performance, but most existing studies have focused on idealized single-shape aggregate rather than mixed-shape aggregate compositions that are common in practice. The present work is an experimental investigation on the influence of coarse aggregate shape composition, individual and systematic blends on workability and compressive strength of M25 grade concrete. Particle characterization was carried out by sieve analysis, flakiness and elongation index tests and by visual inspection. Based on the characterization, eight mixes were prepared with different proportions of flaky, elongated, angular and irregular coarse aggregates at a constant water cement ratio of 0.67. Workability was determined by the slump test (ASTM C143/C143M) and compressive strength was determined at 7- and 28-days using cube specimens tested according to BS EN 12390-3. The results showed that the workability varied significantly with slump ranging from 99 mm to 152 mm and 28-day compressive strength from 24.45 N/mm2 to 35.58 N/mm2. The 100% angular mix achieved the highest compressive strength (35.58 N/mm2) while the 100% irregular mix achieved the highest slump (152 mm) and adequate strength (32.84 N/mm2). A flaky-dominant blend was the only mix that failed to meet the minimum characteristic strength requirement. Among the blended compositions, the blend of 60% angular and 25% irregular, with only 15% of flaky and elongated aggregates gave the best overall balance of workability (131 mm) and strength (32.07 N/mm2). The results show that predominantly angular blend with irregular fractions yields the most consistent performance for M25 grade structural concrete, offering useful insights for aggregate selection and mix design.