Enchancing the Mechanical Properties of Self–compacting Concrete: Means to Achieve a Better Economy in Concrete Construction
Authors: Junior John K. Quarm , Kankam Charles K. 
Published: July 2024

Traditional concrete mixtures that include aggregates from naturally occurring sources offer advantages in terms of strength, workability, and water absorption, as well as a wide range of application possibilities. There is a need to further investigate the enhanced mechanical characteristics of Self-compacting concrete as compared to ordinary conventional concrete.
An experiment on the mechanical properties, comprising compressive strength, split tensile strength, flexural strength, and also density of self-compacting concrete SCC and the corresponding properties of normal conventional concrete (NCC) is outlined in this paper.
Based on the various test results, it is concluded that self-compacting concrete provides better characteristics in terms of durability, strength, and economy in concrete production, although their use should be dependent on the percentage volume of superplasticizer admixture added to achieve higher strength properties in the utilization to substitute conventional concrete (control). In terms of the compressive, flexural, and tensile strength of concrete produced in comparison with both the control and self-compacting concrete, the results still point out clearly that the self-compacting concrete mixes offer the highest compressive, tensile, and flexural strength. The study included 12 cubes, 12 cylinders, and 12 rectangular prisms for the self-compacting concrete, whilst the same numbers were made for the normal conventional concrete. Three (3) specimens each for both mixes were tested on 7,21,28 and 56 days with equivalent cement to aggregate volumes being 1:2:4 (1:6) for the normal conventional concrete and 1: 3.75:2.25(1:6) for the self-compacting concrete. The compressive strength of the self-compacting concrete as compared to the normal concrete (control) offered a percentage increase of 90.44% on the 7th day, a further increase to 98.82% on the 21st day, and reduced to 43.86% on the 28th day and 33.07% on the 56th day. This marginal increase shows that self-compacting concrete offers better compressive strength than conventional concrete even under the same curing parameters and aggregate ratios.  For the split tensile strength, the self-compacting concrete showed a percentage increase of 71.96% on the 7th day, 80.56% on the 21st day, the highest being 98.99% on the 28 days and reduced to 49.55% on the 56th day as compared to the normal concrete (control). This shows that the self-compacting concrete has a better tensile capacity than the conventional concrete(control). This means the self-compacting concrete is the least brittle and has a higher tensile strength than the normal concrete (control). The flexural strength recorded a declining differential percentage increase of 93.24% on the 7th day, 56.59% on the 21st day, 46.53% on the 28th day, and 28.01% on the 56th day. This shows that the self-compacting concrete has a higher ability of composites to resist bending deflection when the force is applied. Hence this was an indirect measure to compare the tensile strength of both the self-compacting concrete and normal concrete(control) and was determined by a third point loading or centre point loading test of the specimen in which the self-compacting concrete specimen proved a higher flexural strength.
Since the self-compacting concrete does not need any vibration during casting, comparing the densities of both self-compacting concrete and the normal concrete (control), the self-compacting concrete shows a higher percentage increase in densities of all specimens. The self-compacting concrete exhibited a higher percentage increase in densities of all the concrete specimens which indicates good durability and less porosity of the concrete.