Study of Compressive Strength of Various Grades of Concrete using Different Sizes of Cubes

Abstract

Concrete being the most versatile material of construction holds the property of stronger in compression. This property enables the concrete for most of its utility in construction. Since the strength of concrete is related to the structure hardened cement paste, it assumes more importance. The size of test specimens for compressive strength is prescribed in relevant codes, however it varies from country to country and often more than one size is permitted.The restraining effect of the platens of the testing machine extends over the entire height of a cube but leaves unaffected a part of a test cylinder. It is, therefore, to be expected that the strengths of cubes and cylinders made from the same concrete differ from one another. It is difficult to say which type of specimen, cylinder or cube, is 'better' but, even in countries where cubes are the standard Specimen, there seems to be a tendency, at least for research purposes, to use cylinders rather than cubes.In the present investigation the effect of different cube size on compressive strength of concrete have been studied. The variations have been made in the size of specimen, grade of concrete & age of concrete. Four different sizes of specimen viz: 150 mm, 125 mm, 100 mm & 75 mm were used. A total of 4 mixes were prepared by varying the grade of concrete mixes. Based on the laboratory results the compressive strength was reported to increase with the decrease in specimen size. Moreover the relative strength of concrete were obtained and it was found that it also increases with the decrease in specimen size and remains unaffected due to age and grade of concrete.