Title: Definition of a PCE Family that Increases Performances when a Workability Retention Agent (WRA) is Added

Author(s): Angela Rozzoni and Michael Dolci

Publication: Symposium Paper

Volume: 329

Issue:

Appears on pages(s): 225-236

Keywords: polycarboxylate polymers; high-range water-reducing admixture; workability retention agent; admixtures for concrete; rheological measurements

DOI: 10.14359/51711217

Date: 9/26/2018

Abstract:
Admixtures for concrete offer a wide range of water reducers that are mostly based on polycarboxylate polymers (PCE) bearing polyethylene oxide nonionic side chains. It is possible to increase PCE effectiveness mixing them with a special workability retention agent (WRA). We focused on ester-based PCE, synthesized from methoxypolyethylene glycol (Mpeg) and acrylic or methacrylic acid, and allylic-type PCE, synthesized from TPeg (polyethyleneglycol isopentenyl ether) or Ipeg (polyethylenglycol methallyl ether) and acrylic or methacrylic acid. By modifyng the composition of the backbone, the kind of repeating units and the molecular weight of polyethylene oxide side chains of PCE it is possible to optimize the properties of the mixture of PCE and WRA. The structures of the most interesting polymers we prepared are described in terms of their conformations (worms or stars). WRA is a particular acrylic polymer that can hydrolyze in alkaline environment; to work properly it must have a certain molecular weight and a low polydispersibility index. If it is used alone it is an ineffective water reducer. To investigate the reason behind this behavior slump test and rheological measured were carried out on mortar.