Updated August 4th, 2017
So when you buy cement there is certain possibility of quality variation in cement. That is why it is essential to test the cement to know its quality not only you paid for this but also to forestall the possibility of a failure through the use of defective material.
The main qualifications demanded of a cement in civil construction are strength, permanency of structure and a rate of setting suitable to the demands of the work.
To determine these qualification both chemical and physical tests are done. But chemical tests aren’t more important than physical tests. So I’ll discuss about physical tests here.
7 Cement Tests to Justify Its Quality
The physical tests which are generally performed to determinethe acceptability of cements are –
- Fineness Test
- Consistency Test
- Setting time Test
- Soundness Test
- Strength Test
- Heat of Hydration Test
- Specific Gravity Test
1. Fineness Test
Fineness is the mean size of cement grain. Fineness test is done to measure the mean size of cement grain.
The finer the cement the surface area for hydration will be large and it increases the strength of cement. But the fineness varies in different types of cement.
Following three methods are applied to test the fineness of cement
- Sieve method
- Air Permeability method
- Sedimentation method
2. Consistency Test
This test is done to estimate the required water quantity to form a normal consistency cement paste. It is defined as the percentage of water required for the cement paste.
3. Setting Time Test
Cement has two types of setting time, one is initial setting time and another is final setting.
Initial setting time is the state of cement mortar or concrete when it starts to become stiffen and unworkable.
Final setting time is the state when cement mortar or concrete has become fully unworkable.
Two methods are used to find the initial and final setting time of cement
- Vicat needle method, and
- Gillmore needle method
4. Soundness Test
Soundness of cement means it doesn’t undergo large volume change after setting. Large changes in volume produce cracks, disintegration and distortion, ultimately leading to failure. So it is very important to test the soundness of cement.
To test the soundness two methods can be applied.
- Le-chatelier method
- Autoclave method
5. Strength Test
Cement has two types of strength – compressive strength and tensile strength.
To know the compressive strength and tensile strength of cement following tests are performed –
Cement mortar cube test (for compressive strength)
- Briqutte test (for tensile strength)
- Split tensile test (for tensile strength)
6. Heat of Hydration Test
Cement produce large amount of heat during hydration process. When large amount of concrete volume is poured the inner temperature is greater than outer surface of concrete. Because outer surface is exposed to weather. Thus surface shrinks rapidly than the inner and tends to produce cracks. That is why it is important to test the heat of hydration of cement.
Following test is performed to know the heat of hydration of cement
- Calorimeter method
7. Specific Gravity Test
Specific gravity of cement is a comparison of weight of a cement volume to the weight of same volume of water.
- Le-chaterlier flask is used to test the specific gravity of cement.
Which test do you think is more important to jusify the cement quality? Share in comments..