V2I12P50

The Impact of Granite, as Sand Replacement, in a Standard Concrete Mixture, Using a Well-Defined Model

Uzoukwu C. S. ^1*, Ogbonna  N. S. M.¹, Abaraogu J. U.¹, Igbojiaku A. U.¹, Anozie R. C.¹, Kalu S. A.¹, Onuoha O. I.¹

Abstract

The study is centered on the impact of granite fine in achieving the best concrete mixture.  Here the sharp is completely replaced with the granite fine and a model was used to carry out the investigation. The work deals more on the investigation of the physical characteristics of the fine aggregates, in addition investigates the effect of partial replacement on the workability and also the extent compression of the concrete mixture. The latter part of the work deals with formulation of a well-defined model for the aim of optimizing the concrete mixture. In the list of experiment carried out include sieve analysis and specific gravity. The manner of water absorption revealed that sharp sand is moderately graded and well-suited for concrete mixture, also the granite fine is poorly graded and with its texture appearing to be finer. The specific gravity of sharp sand was lower than that of granite fine.  With the ration of 2.64:2.75 suggesting a denser material, whereas its water absorption (4.63%) exceeded that of sharp sand (2.05%). This means greater porosity and higher water demand. The strength test conducted as well as the its workability showed that the mix composition significantly influenced concrete performance. From the result obtained, in Mix N1 which contains about 90% sharp sand, the highest slump value of 24 cm (true slump) was recorded. Also, less than 11% granite fine was recorded, which shows superior workability and cohesion. On the other hand, Mix N5 and Mix C24 produced the lowest slump value of about 16 cm (collapse slump), showing reduced workability due to excessive granite fine content. The Mix N45 having a ratio of 0.43:1:0.63:0.53:1.65, comprising 54% sharp sand and 46% granite fine appear to display the compressive strength of 22.89 N/mm². This result not only provided optimal particle packing but also enhances the interfacial bonding.In the other derivation, the  Mix N1 recorded the minimum strength of about 13.11 N/mm², showing that minimal granite fine content reduces matrix compactness. For the research, Scheffe’s model was fomulated and validated to dictate the concrete strength as a function of the mix proportions. Using the Student’s t-test, the model’s accuracy was crosschecked. The calculated t-value (1.70) was less than the tabulated value (2.145) at a 95% confidence level and 14 degrees of freedom. This shows that no significant difference exists between experimental and predicted results. Thus, findings from the research shows the statistical reliability of the formulations and also confirms it to be suitable for concrete optimization within the investigated range. To achieve an effective balance between strength and workability, from the findings, it is recommended that granite fine be used as a partial replacement for sharp sand to achieve an optimized combination between strength and workability.

Keywords:

American Concrete Institute, Superplasticizers, profile sheet, polystyrene beads, Agro fibre, Degrees of freedom