Finding out the factors like Initial setting time, Final setting time, and soundness of cement a parameter named Standard Consistency is used. Standard Consistency is the amount of water required to make cement paste plastic.
This article gives detailed explanation on Standard Consistency Test of Cement and how to calculate it?
Consistency of Cement is amount of water required to initiate the chemical reaction between cement and water to make the uniform cement paste.
Standard Consistency of Cement is defined as Consistency which will permit Vicat plunger with 10mm diameter and 50mm length to penetrate to a depth of 33-35mm from top of the mould.
Standard Consistency of Cement can also be defined as Consistency of cement which will permit Vicat plunger to penetrate to the point 5-7mm from the bottom of the mould.
Also Standard Consistency means the amount of water required to make Cement Paste Plastic.
Factors affecting the strength of concrete tells us that Material used and water-cement ratio are some of the major factors that affects the strength of concrete. Cement and water are the major materials in concrete.
To attain the design strength we need to add right amount of water in concrete. Adding water less than Standard Consistency will provide less suitable environment for water cement reaction and ultimately less heat of hydration and less strength.
Addition of water more than the Standard Consistency can result in segregation and also reduction in strength.
To avoid these kind of situations it is important to know the Standard Consistency of Cement.
Standard Consistency of Cement helps us choose the right amount of water for producing effective concrete which will ultimately result in higher strength.
Note: Standard Consistency of an OPC varies between 25-35%. That means we need a minimum of 25% of the water in volume to make a standard consistency of cement depending on the cement type.
Lets assume Cement we got is having Standard Consistency of 30% and we have to calculate amount of water for 100 gm of cement then
100 x 30% = 30gm
That means 30gm of water is required to produce a Consistent paste of 100gm of cement.
To determine quantity of water required to produce a cement paste of Standard Consistency.
A device used to determine Standard Consistency and Setting Times consists of rod weighing 300 grams, having a needle at one end and supported in the frame with Graduated scale for measuring the Penetration. Also having a mould to put the cement.
It is small rod type needle made of Polished Brass with 10 ± 0.05 mm diameter and 50mm length with projection at upper end. The lower end is flat..
Vicat mould is having internal diameter 80 mm and 40 mm height. With non-porous base plate is provided at the base of the mould. Mould is having suitable clamping ring.
To take the weight of Sample of Cement. It should at least be with least count of 1 gram.
|Sr. No.||Weight of cement (gram)||Percentage of water by dry cement (%)||Amount of water added (ml)||Penetration (mm)|
Standard Consistency = (Quantity of water for 33 mm to 35mm penetration from top/Weight of cement) X 100
Standard Consistency of given Cement is : __________
Gauging Time is a time span between the addition of water to cement and filling the mould.
Standard Consistency is also called as Normal Consistency and defined as amount of water required to make Cement paste plastic.
Standard Consistency of an OPC varies between 25-35%. That means we need a minimum of 25% of the water in volume to make a standard consistency of cement depending on the cement type.