Introduction

Cement is undoubtedly a crucial component of every construction activity. The quality of the concrete boils down to the quality of cement used, and good quality concrete is required to provide strength and durability to the building. This is where the cement test comes into play. Cement tests are conducted before beginning construction work, for determining the strength and quality of the cement. It helps identify the use of cement for different purposes, which is dictated by the soundness and performance of the cement. 

Various properties of cement, like consistency, fineness, strength, and specific gravity are determined by several cement testing methods. The tests for these properties of cement are explained below.

Types of cement test

Cement tests are classified into two categories, namely

1. Field Test
2. Laboratory Test

Field test

A rough estimate of the quality and purity of cement can be understood by following the given steps

• The colour of the cement must be greenish-grey.
• It should feel smooth when rubbed between fingers.
• When a hand is inserted into a cement bag, it should feel cool.
• It should not feel oily on touching.
• Dry cement thrown into a bucket of water should float for some time.

Laboratory test

Laboratory test is also known as the physical test of cement. There are 8 different types of laboratory tests, as mentioned below

1. Fineness test
2. Consistency test
3. Heat of hydration test
4. Tensile strength test
5. Soundness test
6. Setting time test
7. Chemical composition test
8. Compressive strength test

Fineness test

Fineness test is done to measure the size and proper grinding of cement particles. It is responsible for the rates of hydration, evolution of heat and gain of strength. More the surface area, finer are the grains, and faster is the development of strength. The fineness of cement is evaluated by the Sieve test.

For the Sieve test, a standard IS sieve is used. Cement is sieved continuously for 15 seconds in a circular and vertical motion. The leftover cement on the sieve is weighed, and it should not cross 10% for normal cement and 5% for rapid hardening cement. The fineness of cement is determined using a 90-micron sieve as per IS 4031(Part 1):1996.

Consistency test

Consistency test is done to determine the amount of water required to produce a cement paste. It is conducted using a Vicat’s apparatus. A Vicat’s apparatus is 50 mm in length and 10 mm in diameter. The amount of water required is determined by taking 300 gm of cement in the apparatus and creating a 33-35 mm hole into the mould from the top.

The percentage of water for normal consistency is calculated by P = (W1/W)/100

Here, W = Weight of cement taken

           W1= Weight of water for desired penetration

The IS codes for the consistency test of cement are IS 5513:1976 and IS 4031 (Part 4):1988.

Heat of hydration test  

The heat of hydration refers to the exothermic chemical reaction between cement and water. During this process, heat is produced. The heat rise could be as high as 50 degrees celsius. And to avoid the release of this excess heat, low heat cement is used. The heat of hydration is carried out using a calorimeter.

The standard IS code for the heat of hydration is IS 4031:1968.

Tensile strength test

The tensile strength of cement refers to the maximum load it can take in the hardened state without having any crack in its structure when tension is applied. It is lower as compared to compressive strength. A cement-mortar briquette in a tensile testing machine is used for this test.

The IS code for tensile strength is IS 456:2000.

Soundness test

The soundness test of cement is conducted to calculate the stability of the mix during the process of setting and hardening. The aim is to identify if there is the presence of excess free lime and magnesia in the cement. In cases of volume change, the mix is unstable in its setting and hardening, and if there is a crack in the concrete, then it is known to be of poor dimensional stability. The soundness is conducted using a Le-Chatelier apparatus.

The IS code for soundness of cement is IS 4031(Part 3):1988.

Setting time test

The setting time test is done to understand how much time is taken by the cement to lose its plasticity and when it starts gaining strength to resist pressure. The initial setting time is the time by which the cement starts losing its plasticity, and the final setting time is the time taken by the paste to reach the final stage and become a hard mass. The setting time test is done using a Vicat apparatus.

The initial and final setting time is given as of IS 4031(Part 5): 1988.

Chemical composition test

The chemical composition test is conducted to calculate the rate of raw materials present in the cement. These components include limestone, silica, and alumina among others. The general composition of cement is given below

• Limestone- 62%
• Silica- 22%
• Alumina- 7.5%
• Magnesia- 2.5%
• Other components- 6%

The IS code recommended for keeping a check on the chemical composition of cement is IS 269: 1998.

Compressive strength test

It is conducted to test the ability of the structure to undergo compression. The lower the number of cracks and fissures, the higher its compressive strength. Factors affecting compressive strength are water-cement ratio, cement-sand ratio, and manner of mixing, type of sand, size of the specimen, curing condition, and rate of loading.

The IS code for the compressive strength of cement is IS 4031 (Part 7): 1988. 

These are the tests that are conducted to test the quality and durability of the cement. Hopefully, this article was able to clarify your concept about different cement tests. Explore our specialized cement products in our cement product listings that align seamlessly with the testing methods discussed in our blog.