Comb polymer architecture effects on the rheological property evolution of concentrated cement suspensions

Glen H. Kirby, Jennifer A. Lewis

Research output: Contribution to journalArticlepeer-review


We have studied the rheological behavior of concentrated cement suspensions in the absence and presence of comb polymers comprised of a polyacrylic acid (PAA) backbone and charge-neutral, poly(ethylene oxide) (PEO) teeth. These species possessed a uniform backbone molecular weight and graft density, with varying teeth molecular weight. Both PAA, a linear polyelectrolyte, and PAA/PEO comb polymers imparted initial stability to concentrated cement suspensions above a critical weight fraction, w*of 4 mg/(g of cement). Cement- PAA suspensions, however, set prematurely. Their rapid, irreversible stiffening stemmed from deleterious interactions between PAA and multivalent counterions in solution. Interestingly, the presence of PEO teeth comprised of only a few monomer units in length mitigated such interactions. The rheological property evolution of concentrated cement-PAA/PEO suspensions exhibited complex behavior ranging from the reversible gel-like response observed at short teeth lengths to a remarkable gel-to-fluid transition observed during the deceleratory period for systems comprised of longer PEO teeth. At longer hydration times, all cement-PAA/PEO suspensions exhibited initial elastic modulus values, Gi ∼ exp(t/τc) before the onset of the acceleratory period, followed by initial set. Their characteristic hydration time, τc, and set time depended strongly on the concentration of "free" carboxylic acid groups [COO-] arising from non-adsorbed polyelectrolyte species in solution.

Original languageEnglish (US)
Pages (from-to)1643-1652
Number of pages10
JournalJournal of the American Ceramic Society
Issue number9
StatePublished - Sep 2004
Externally publishedYes

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry


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