This Article is specially authored by young and enthusiastic Mr. Mukund Paprikar , for our blog
Cement is just like the oxygen for majority of the buildings and specially for RCC framed construction.
Whenever we think of any mortar or concrete , we invariably consider the cement mortar or the cement concrete.
It is therefore essential , to only use cement which is of assured quality for the construction .
This article beings forth certain simple field tests which you can carry out yourselves at the site to assess the suitability of the cement .
Basic parameters :
We buy cement as per the grade.
Ordinary Portland cement is available in Grades 43 & 53 whereas Pozzolona Portland cement comes in Grade 33 only ( Although this grade is not printed on the bag for PPC )
Normally test certificates are made available by the cement manufacturers along with each consignment of the cement .
For further verification , the cement can be sent to the recognized test labs for testing.
Thus , the test results shall indicate the suitability of the cement . The laboratory tests include : Compressive strength , consistency test , residue test etc .This might take more than 28 days to get the results and hence it may not be possible to immediately point out whether or not to use a particular batch of cement at site.
Therefore , it is essential that certain preliminary assessment is made at the site by the site personnel :
Field tests for cement :
These are derived by the experience of the construction personnel and can give rough indications about the unsuitability of cement .
It is suggested that each site person is familiar with these simple tests so that a quick assessment can be initiated at site it self.
Group A : By Appearance and Feel :
1.The color of cement should be uniform . Preferably greenish grey.
2.Open the bag and observe the cement .There should not be any lumps visible .If any lumps are found , press the lumps between fingers. If it becomes powder ( without lumps ) , it is alright . In case , lumps are still seen even after pressing , it means that cement is already set and is not suitable.
3. Insert the palm inside a cement bag , the cement should feel cool to the palm. If it is cool it is quite alright.
4.Take a little cement in the pinch and rub it by fingers . If the feel is gritty , it means setting has began in the cement.
5.Cement should not feel oily when touched with fingers.
Group B : With Water :
6. Throw a hand full of cement on the water surface inside the bucket . If the cement floats on surface , the quality is acceptable but if it sinks in the water , it is carrying impurities.
7.Take about 100 gm of cement and make a stiff paste by adding very little water .Form a cake out of this paste and place it on a glass plate. The cake should retain its sharp edges.
Submerge this plate with cake in the water in a bucket .After 24 hours , the cake should not lose its shape and must have attained some strength.
Note from the Blog :
Dear Reader ,
Some more photographs are to be uploaded
Please give us a day or two for bringing the photos which shall demonstrate the various field tests with clarity.