Upload
chantale-holland
View
17
Download
0
Embed Size (px)
DESCRIPTION
Concrete Superplasticizers. By Felipe Perez. 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. - PowerPoint PPT Presentation
Citation preview
Concrete Superplasticizers
By
Felipe Perez
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
References http://www.chemisol.com http://www.edpsciences.org http://www.fhwa.dot.gov/infrastructure http://www.fritzpak.com http://www.precastconcretebc.com http://www.reefball.org/adva