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Concrete Superplasticizers
What is a superplasticizer
Developed in the 1960’s First used in Japan and
Germany Introduced in the U.S. in the
1970’s Neutralizes the surface
charges Causes dispersion Releases water in cement
particles Reduces viscosity
Linear polymers containing sulfonic acid groups
Sulfonated melamine-formaldehyde condensates
Sulfonated nephthalene-formaldehyde condensates
Modified lignosulfonates
Polycarboxylate derivatives
Main Purpose Produce flowing
concrete (7”-9” slump increase)
Easy placement (picture: concrete will fill all gaps between rebar)
High-strength (reaches up to 14,000 psi in 7 day break)
Important factors Type of plasticizer
Dosage
Time of addition of superplasticizer
Amount of cement
Benefits Reduce machine wear
(concrete on picture will go from this 1” slump to 9” slump)
Better surface texture Improve strength in
less time Reduce absorption Eliminate fine cracks
Disadvantages
High cost
Brief action (picture: restoration of the Queen Isabella Causeway after collapse in Sep. 15, 2001, time was very important)
Need strong, sealed forms
Disadvantages
High cost
Brief action (picture: restoration of the Queen Isabella Causeway after collapse in Sep. 15, 2001, time was very important)
Need strong, sealed forms