Keywords: Bureau of Indian Standards, BIS, compressive strength, density, compaction factor, flaky aggregates, elongated aggregates, concrete strength, concrete workability, flakiness
Combined effect of flaky and elongated aggregates on strength and workability of concrete
Combined effect of flaky and elongated aggregates on strength and workability of concrete has often been qualitatively expressed. This work aims at establishing the same quantitatively. M 25 grade concrete for different ratios of weights of elongated to flaky aggregate and angular to total aggregate were tested for compressive strength, density and workability. The results reveal that the effect of elongated aggregates is more than flaky aggregates, on the characteristic compressive strength of concrete. Concrete with 1:1 ratio of flaky to elongated aggregates possesses minimum weight. For a constant EA:FA ratio, density increases but characteristic compressive strength and compaction factor decrease with decrease in AA:TA ratio. For a constant AA:TA ratio, characteristic compressive strength and compaction factor are maximum and density of concrete is minimum for a EA:FA ratio of 1:1. Though the results and observations cannot be generalised within the scope of this work, they can definitely impress on the structural engineers and editors of standard codes of practice of different countries that the flakiness and elongation indices have to be calculated for course aggregate being used in concrete and necessary strength reduction factors have to be adopted.