Superplasticizers

about brief explanation of super plasticizers

1. Super Plasticizers
B.Joy Dason 19PA1A0107
Ch.Manikanta 19PA1A0115
K.jagadeesh 19PA1A0122
K.V.N.S.Vamsi 19PA1A0128
P.Vinod Kumar 19PA1A0142
V.Tarun Satya Kumar 19PA1A0151
P.M.S.N.Srinivas 20PA5A0105
II-II Civil
Vishnu Institute Of Techonology

2. Super plasticizers
●Super Plasricizers are high Water range reducing
Agents are additives used in making high strenght to
Concrete
●Super Plasticizers allow reduction of water content
by 30% or More
●It is improved version of Plastizers which was
developed in Japan and Germeny in 1960 to 1970

3. ●It gives Production of flowing,self levelling,and
self compacting .
●Production of high strength and high
performance of Concrete.
●They are Chemically different from normal
Plasticizers .

4. ●With Super plasticizers It is possible to use w/c
as low as 0.25 or even lower .
●Use of Super Plasticizer – fly ash, slag and
particularly Silica fume to make high
performence Concrete .
●Super Plasticizers are more powerful as
despersing agents and they are high range
water reducers .

5. Super Plasticizers can produce
●At the w/c Ratio much more workable concrete
than the plane ones .
●For the same worability,it permits the use of lower w/c
ratio .
●As a consequence of incresed strength with lower w/c
ratio ,it permits reduction of cement
content .

6. Classification of superplasticizer
●Sulphonated melamine – formaldhyde condensates
( S M F ) .

●Sulphonated naphthalene – formaldehyde condensates
(S N F )
●Modified lignosulphonates ( M L S )

7. Effects
●No dramatic improvement in workability-zero
slump .
●Initial slump of about 20 mm to 30 mm fludized
by super plastizers at normal dosages .
●High dosage is required to fluidify no slump
concrete .

8. Compatibility of superplasticizers
and cement
●It has been noticed that all superplastizers are not
showing the some extent of improvements in fluditity
with all types of cements .
●Some of the superplastizers may show higher
fludising effect on the some type of cement than
other cement .
●Compatibility problem looks like very complex .

9. Field tests to determine optimum
dosage of the superplastizer
●Marsh cone test
●Mini slump test
●Flow table test

10. Marsh cone test
●Marsh cone is a coniacal brass vessel,which has a smooth aperture at
the bottom of diameter 5 mm.
Procedure :
●Take 2kg cement,proposed to be used at the project.
●Take 1 liter of water (w/c = 0.5 ) and say 0.1% of plasticizer .
●Mix them thoroughly in a mechanical mixer for 2 min .
●If hand mixing is done, the slurry sholud be sieved throgh 1.18
sieve to exlude lumps.

11. ●Take 1 liter slurry and pour it into marsh cone duly closing the
aperture with a finger.
●Start a stop and simultanesusly remove the finger .
●Find out the time taken in seconds,for complete flow out the slurry.
●The time in seconds is called the “Marsh cone” .
●Repeat the test with different dosages of plasticizers.
●The dose at which the marsh cone of time is lowest is called the
“saturation point ” .

12. Effect of superplasticizer on the
properties of hardened concrete
●Since plasticizers and super plasticizers improve the workability and
facilitate reduction on w/c ratio,and thereby increase the strength of
concrete .
●Hence the use of superplasricizers is a pragmatic step to improve all
round properties of hardened concrete.
●No bad effect upto only 3% by weight of cement .
●Only if the bad quality lignosulphonate based plasticizers .

13. Factors effecting the workbility
●Type of superplasticizers
●Dosage
●Mix composition
●Mixing procedure
●Equipments
●Others

14. Site problems in the use of
superplasticizers
●Slump of reference mix .
●Problem with crusher dust and dust .
●Compatibility with cement .
●Slump loss .
●Finishing .
●Removal of form work.