Can we add plastisizers in hand mixed and mechanical mixed concretes of grade M20? If yes what type and how much quantity?
Plastisizers
- Thread starter rashi
- Start date
Dnyan Deshmukh
Staff member
Plasticizers are used to modify the workability of concrete without adding water to gain the workability.
Example: if you produced a concrete of M20 grade by adding water as per water cement ratio and water required by aggregate which is termed as absorption by aggregate. produced mix might be stiff or of low workability.
Workability of concrete can be achieved by either addition of water or by addition of plastcizers in concrete.
Adding water to gain workability will lead to reduction in strength.
Admixtures does this job of improving workability without adding water in it.
Water required to get desired workability is reduced by admixture ( this is water reduction capacity of admixture used)
Capacity of reduction in water varies with admixture brands and their compatibility with cement.
As the formulation of each admixture is done by respective companies base on requirements and price bracket, you will find big range of admixture available in market.
You can select few brands as per your requirement and budget and do trials with it to find which one performs best for you.
The admixture dosage is purely depend on type of admixture you are using and its chemical formation.
Normally the dosage of admixture can be from 0.1% to 1.2% by weight of cement.
You can even proceed with higher dosage of admixture by doing trials to ensure there is no delay in setting of concrete produced with it.
Plasticizers can be added in Hand Mix, Mechanical mix, in hand or manual mixing, mixing efforts need to be more to ensure uniform mix of concrete.
You can use normal range plasticizer which are mostly retarders with low water reduction capacity.
You can start dosing from 0.1% and increasing dosage till you get the desired results.
Once you find the optimum dosage %, you can do several trial batches and verify the compressive strength on concrete to proceed further for using that admix at % you found satisfactory.
Example: if you produced a concrete of M20 grade by adding water as per water cement ratio and water required by aggregate which is termed as absorption by aggregate. produced mix might be stiff or of low workability.
Workability of concrete can be achieved by either addition of water or by addition of plastcizers in concrete.
Adding water to gain workability will lead to reduction in strength.
Admixtures does this job of improving workability without adding water in it.
Water required to get desired workability is reduced by admixture ( this is water reduction capacity of admixture used)
Capacity of reduction in water varies with admixture brands and their compatibility with cement.
As the formulation of each admixture is done by respective companies base on requirements and price bracket, you will find big range of admixture available in market.
You can select few brands as per your requirement and budget and do trials with it to find which one performs best for you.
The admixture dosage is purely depend on type of admixture you are using and its chemical formation.
Normally the dosage of admixture can be from 0.1% to 1.2% by weight of cement.
You can even proceed with higher dosage of admixture by doing trials to ensure there is no delay in setting of concrete produced with it.
Plasticizers can be added in Hand Mix, Mechanical mix, in hand or manual mixing, mixing efforts need to be more to ensure uniform mix of concrete.
You can use normal range plasticizer which are mostly retarders with low water reduction capacity.
You can start dosing from 0.1% and increasing dosage till you get the desired results.
Once you find the optimum dosage %, you can do several trial batches and verify the compressive strength on concrete to proceed further for using that admix at % you found satisfactory.
