10-04-2017, 09:01 PM
Concrete is a composite material composed mainly of aggregates (fines and coarse), cement and water. Cement and aggregates remain the main constituents, while aggregates alone constitute an important part of the volume of concrete. According to Alexander and Sydney (2005), between 70 and 80 percent of the total volume of concrete is occupied by the aggregate. With this large proportion of aggregate-occupied concrete, the aggregate is expected to have a profound influence on concrete properties, cost of production and overall performance. The aggregates are usually coarse gravel or crushed rocks such as limestone or granite along with fine aggregate such as sand. These are responsible in part for the durability, quality and strength of the resulting concrete. Portland cement and other cementitious materials such as fly ash and slag cement etc. Serve as a binder for the aggregates, while various chemical mixtures may be added to achieve varied properties.
Classification and maximum aggregate size are important parameters in any concrete mix. They affect relative proportions in the mixture, the workability, the economy, the porosity and the contraction of the concrete, etc. Experience has shown that very fine sands or very thick sands are objectionable; The former is uneconomical, the latter gives harsh and impractical mixtures. Therefore, the purpose of this work is to find the best finite sand modulus to obtain the optimal classification of the aggregate (all in aggregate), which is the most appropriate, and for the economy. In general, the classification of aggregates, which do not have a deficiency or excess of any aggregate size and give a smooth classification curve, produce the most suitable concrete mix. In addition, a cohesive mixture is also desired for the pumped concrete produced by RMC Plant. In the present research, we have investigated the effect of grading the river sand particles for a good mix of concrete. Sand has been classified into three categories, ie fine, medium and coarse. These were mixed with coarse aggregates in different proportions to keep the finite combined (all-in-added) modulus more or less the same. Various proportions of said aggregate are mixed in the preparation of the mixture of concrete M30. The effect on concrete workability, cube strength, flexural strength and permeability is studied. The results indicate that with the change in the fineness of the sand, the workability is affected.
Classification and maximum aggregate size are important parameters in any concrete mix. They affect relative proportions in the mixture, the workability, the economy, the porosity and the contraction of the concrete, etc. Experience has shown that very fine sands or very thick sands are objectionable; The former is uneconomical, the latter gives harsh and impractical mixtures. Therefore, the purpose of this work is to find the best finite sand modulus to obtain the optimal classification of the aggregate (all in aggregate), which is the most appropriate, and for the economy. In general, the classification of aggregates, which do not have a deficiency or excess of any aggregate size and give a smooth classification curve, produce the most suitable concrete mix. In addition, a cohesive mixture is also desired for the pumped concrete produced by RMC Plant. In the present research, we have investigated the effect of grading the river sand particles for a good mix of concrete. Sand has been classified into three categories, ie fine, medium and coarse. These were mixed with coarse aggregates in different proportions to keep the finite combined (all-in-added) modulus more or less the same. Various proportions of said aggregate are mixed in the preparation of the mixture of concrete M30. The effect on concrete workability, cube strength, flexural strength and permeability is studied. The results indicate that with the change in the fineness of the sand, the workability is affected.
