Brief analysis of compressive strength of concrete

The compressive strength of any material is described like the defiance to failure under the operation of compressive forces. Compressive strength is considered as the vital element to detect the operational activity of the material (specifically for concrete) throughout service conditions.

Concrete mix is designed or measured to get the necessary engineering and strength properties useful for the design engineer. Some of the other engineering properties of solidified concrete contain Elastic Modulus, Tensile Strength, Creep coefficients, density, coefficient of thermal expansion etc.

The comprehensive strength of concrete is set in batching plant laboratories for each batch so that the optimal quality of the concrete is achieved throughout casting. The strength of concrete plays an important role to work out the durability of the members. Concrete specimens belong to cast and are verified under the operation of compressive loads to find out the strength of concrete.

In order to measure the compressive strength, just divide the failure load with the area of application of load, generally after 28 days of curing. The strength of concrete is managed by proportionating the cement, coarse and fine aggregates, water, and different admixtures. To find out the stability of concrete, the percentage of the water to cement is considered as the most vital factor. If the water-cement ratio is low, the compressive strength will be high.

The capacity of concrete is defined in psi - pounds per sq. inch in US units and in MPa - mega pascals in SI units. This is generally named as the characteristic compressive strength of concrete fc/ fck. For typical jobsite uses, the stability of concrete will differ from 10Mpa to 60 Mpa. For specific uses and structures, concrete mixes are designed to acquire very high compressive strength capability in the range of 500Mpa, generally defined as Ultra High Strength Concrete or Powder Reactive Concrete.

There are standard tests to obtain the strength which range from Cube Test and Cylinder Test. Both the tests differ in the shape of test specimens. In Indian, British and European standards, the Compressive strength of concrete is obtained by analyzing concrete cubes stated as characteristic compressive strength but in American standards Cylinder strengths are applied in RC and PSC design. It is achieved by examining concrete cylinder specimen. However, empirical formulas are utilized to transform cube strength to cylinder strength and contrary.

Ref.: civildigital.com