Title: Optimizing Polycaboxylate Polymers

Author(s): I. Schober and R.J. Flatt

Publication: Symposium Paper

Volume: 239

Issue:

Appears on pages(s): 169-184

Keywords: adsorption; concrete; flow retention; mortar; paste flow; polycarboxylate ether; polymer structure; SCC; superplasticizer

DOI: 10.14359/18378

Date: 10/1/2006

Abstract:
Polycarboxylate polymers as superplasticizers have revolutionized concrete technology in the past years. Today most of SCC and high performance or ultra high strength concrete is produced with this new kind of polymers. Their comb-like structure consisting of an ionic backbone and non-ionic polyalkylene glycol side chains offers a huge "playground" for polymer design. Polymers with different side chain chemistry, length, grafting density as well as with different backbone ionic content, structure and length are on the market, which offers the customer an almost confusing range of superplasticizers. Different concrete applications often require different and chemically optimized superplasticizers. The universal admixture is still a challenge for the researchers. In order to better understand the structure-performance relationship of polycarboxylates, systematic variations of comb type superplasticizers were produced in the laboratory and the influence of the changes in polymer structure on the performance in cement paste, mortar and concrete was studied. Clear effects of the structural changes on the performance regarding water reduction, flow improvement and slump retention can be shown. They stress the importance of a good adsorption and adequate surface coverage to achieve good dispersion. All can be directly influenced by the polymer design depending on the desired properties of the superplasticizer.