Concrete is a unique and main product in the field of construction, maintaining its quality is must for the successful completion of the respective project. Quality tests on concrete is much more important as the manufacturing process of concrete includes multiple constituents – cement, sand, metal or aggregate, water, and admixtures and constituents with different properties. Although the priorities and requirements of the project team is necessary, concrete should meet the test standard. The possible main reasons to test the quality of concrete are as follows,
1) In order to check the quality difference of concrete between the given specifications to the supplied standard of mixture.
2) To identify whether the concrete has meet its required strength for the planned purpose.
3) To determine whether the prepared concrete structure is ready to use or not.
Although the availability of quality tests are many it is not possible to test with all the available tests as they consume much time and cost. So it is very much important to understand the purpose of quality tests. The following are the available quality tests on hardened concrete and fresh concrete,
|Quality tests on hardened concrete||Quality tests on hardened concrete|
|· Compressive strength or Cube test||
· Work-ability Tests – Slump Test and others
|· Tensile strength||· Bleeding;|
|· Direct tension||· Segregation resistance|
|· Modulus of rupture||· Unit weight|
|· Density||· Wet analysis|
|· Shrinkage||· Temperature|
|· Creep||· Heat generation.|
|· Freeze/thaw resistance|
|· Resistance to aggressive chemicals|
|· Analysis for cement content and proportions|
|· Ultrasonic, nuclear.|
Many of these quality tests can be included within two main tests namely, Compressive strength or cube test and slump test. The reasons for selecting these two tests as main are as follows.
- When comparing many of the properties are related to the compressive strength of concrete.
- Easy, cheap and accurate results could be achieved from these tests.
- To check the water – cement ratio and other component ratio these tests are more effective.
- These tests help to determine the concrete quality before starting the placement of concrete.
- These two tests can be done on work site and they don’t need any expensive equipment or testing work space.
What is compressive test?
Normally, after twenty eight – 28 days of curing the cast concrete specimens are tested under the action of compressive loads to determine the strength of concrete.
A test that could be conducted on site to determine the workability and the consistency of freshly prepared concrete.