Cylinder Test of Concrete

The cylinder test of concrete is used to determine the compressive strength of concrete.

The compressive strength of concrete is one of the most basic things considered when designing structures. The Cylinder Test of Concrete is the alternative to the concrete cube test. In some countries, a cube test is performed and in others, a cylinder test is performed.

Here, the compressive strength of a concrete cylinder is determined by continuously applying a load to the cylinder until failure occurs. The test is carried out on a compression machine.

Apparatus

The prepared sample cylinder can be one of the two sizes mentioned below. The diameter of the casting cylinder must be at least three times the nominal maximum coarse aggregate size used for concrete production. The equipment you will need is:

• Compression testing machine.
• Cylinder mold of 150mm diameter and 300mm height or 100 x 200mm.
• Weighing balance.

Test Procedure

Sample cylinders are cast from steel, cast iron, or any other form of non-absorbent material. Even in difficult conditions, used molds must retain their original shape and dimensions. The formwork must support the concrete without leaks. Before pouring the concrete mixture into the mold, the inside of the mold must be thoroughly greased so that the hardened cylinder can be easily removed. The concrete mixture is laid out in molds with a layer of at least 5 cm. The number of strokes per layer during compaction must be at least 30. Compaction should reach the base layer so that most of the pores can escape. Samples are stored in an untouched place indoors with a relative humidity of at least 90% at a temperature of 27° ± 2°C for 24 hours. After this period, a sample is taken and immersed in clean, freshwater until a trial period is reached.

Here is the step by step procedure:

• Concrete cylinders are cast to standard sizes and cured for 28 days.
• For testing, three specimens of the same size are cast.
• Remove the sample from the curing tank.
• Remove excess water from the sample surface.
• Place the specimen vertically on the platform of the compression tester.
• A cap on the end of the cylinder facilitates even application and load distribution.
• Make sure the load platform touches the top of the cylinder before applying the load.
• Continuous, uniform loading without impact at a rate of 315 kN/min.
• And keep uploading until the sample fails. Record the maximum load.
• The test is repeated for the remaining two specimens. Test minimum 3 specimens.

Calculations

Compressive strength = (Maximum load/ Cross-sectional area)

Result 

The 28th-day compressive strength of cylinder =…………………….N/mm²