The splitting tensile strength test is performed on hardened concrete to determine its tensile strength. Marginal variations in water to cement ratio, ingredient proportioning, increase in a slump, etc impacts the desired concrete strength. This in turn affects the strength and stability of structures. There are several tests to determine the strength of concrete.
Quality tests are to be conducted on concrete at various stages starting from the production stage to the hardened stage, and on structures. Quality tests play an important role in ensuring the construction quality. This article covers splitting tensile strength test for deriving the strength of concrete
Quality tests on concrete
The Quality tests are done on different stages like production stage, hardened stage and Non destructive tests.
Quality tests on Fresh concrete
Quality tests on hardened concrete
- Compressive strength
- Tensile strength – Split tensile strength
- Flexural strength test
- Water absorption test
Non destructive tests on concrete
- Rebound hammer
- Penetration resistance test
- Ultrasonic pulse velocity test
In this article we deal with the Splitting tensile strength test of concrete.
Splitting tensile strength test – Significance
Since concrete is brittle, it is weak in tension and can cause cracks. So it is essential to conduct the tensile strength test of concrete. A method of determining the tensile strength of concrete using a cylinder which splits across the vertical diameter. It is an indirect method of testing tensile strength of concrete. At least three samples should be tested and an average value is calculated. The main objectives of this test are as follows
- For determining the tensile strength of concrete.
- To provide the information on the use of sand and aggregate.
- To determine the uniform stress distribution.
- For studying the behaviour of concrete.
- IS 5816: 1999
- ASTM C496
- Testing machine
- Plate or Supplementary Bearing bar
- Bearing strips
- Cylinder specimen
- Tamping rod
The testing machine should apply continuous load without shocks. So for this test, two bearing strips with 3.2 mm thick and 25 mm wide are used. The dimension of the cylindrical specimen is 150 mm in diameter and 300 mm in height.
Test procedure of Splitting tensile strength test
- The first step is to prepare the concrete mix for making the cylindrical specimen.
- Grease the inside surface of the mould and Pour the mix into the mould as layers.
- Compact each layer using a tamping rod. Tap each layer 30 times.
- Uniformly stroke the concrete mix and remove the excess concrete.
- Then immerse the casted specimen in water for 24 hours at 27-degree celsius.
- After that remove the specimen from the mould and immerse it in freshwater.
- The splitting tensile strength of concrete should be conducted at 7, 28 days of curing.
- Before starting the test, take the specimen from the immersed water and wipe the water.
- Then note the dimension and weight of the specimen.
- Place plywood strip above and below the specimen
- After that place the specimen on the testing machine.
- Then gradually apply load at a rate of 0.7 to 1.4 MPa/min (1.2 to 2.4 MPa/min based on IS 5816 1999).
- Record the load at which the specimen breaks.
Calculation – Splitting tensile strength test
Splitting tensile strength of concrete, T= 2P/ Ω LD
The unit of tensile strength is N/mm. The splitting test is easy to perform and we can get uniform results. It is a simple, reliable and convenient method to determine the strength of concrete.