Overall Strength of a structure such as flexural resistance and abrasion directly depends upon the compressive strength of concrete. According to Wikipedia, Compressive Strength of concrete is defined as the Characteristic strength of 150mm size concrete cubes tested at 28 days.
" The compressive strength of concrete is given in terms of the characteristic compressive strength of 150 mm size cubes tested at 28 days (fck). The characteristic strength is defined as the strength of the concrete below which not more than 5% of the test results are expected to fall."
The strength of the final mortar is strongly dependent on the type of materials and the ratio of the components, and testing is required to determine the correct proportions for each application. ASTM C109 describes the methodology for testing the compression strength of mortars using cubes of material that are 2 inches on a side.
Strength of cement is the most important of all the cement properties. Grades mentioned in the cement bags as 53/43 grade OPC/PPC in fact represent the strength of the cement. 53 Grade OPC Cement simply means that 28-days compressive strength of the cement -mortar cubes prepared out of that cement in a standard manner will be of 53 MPa.
1.1 This test method covers determination of the compressive strength of hydraulic cement mortars, using 2-in. or [50-mm] cube specimens. Note 1: Test Method C349 provides an alternative procedure for this determination (not to be used for acceptance tests).
This standard covers the requirements of the moulds used for casting cement or concrete cubes,cylinders and beams for tests of cement and concrete, such as compressive strength test and flexural strength test. c) Beam moulds of 100 x 100 x 500 mm and 150 x 150 x 700 mm, d) Bar moulds of 25 x 25 mm ...
The compressive strength of cement mortar is principally determined by two methods, either by cubes or by prisms. In the cube method, the compressive strength is evaluated by directly subjecting the cube specimens to compressive load, where as in the prism method, the standard mortar prism (4×4×16cm) is first broken to two halves by flexural test, and then each half prism is subjected to ...
Procedure: Compressive Strength Test of Concrete Cubes For cube test two types of specimens either cubes of 15cm X 15cm X 15cm or 10cm X 10cm x 10cm depending upon the size of aggregate are used. For most of the works cubical moulds of size 15cm x 15cm x 15cm are commonly used.
Strength test are not done on neat cement paste because of difficulties of excessive shrinkage and subsequent cracking of neat cement. Strength of cement is indirectly found on cement – sand mortar in specific proportion.The cubes are prepared for this purpose.
Cement mortar as in a mix of sand and cementitious materials. The 7 day compressive strength in MPa is merely the load at failure of a (typically) cube specimen when tested in the standard way, divided by the loaded area of the specimen in square mm.