PAA/PEO Comb Polymer Effects on the Rheological Property Evolution in Concentrated Cement Suspensions
A new oscillatory shear technique was developed to probe the rheological property evolution of concentrated cement systems. The rheological property evolution of ordinary and white Portland cement systems were studied in the absence and presence of pure polyelectrolytes and PAA/PEO comb polymers with a wide range of PAA backbone molecular weight, PEO teeth molecular weight, and acid:imide ratio. Cement-PAA suspensions experienced rapid irreversible stiffening and set at 6 min due to ion-bridging interactions between the PAA-coated particles and dissolved Ca2+ counterions. In contrast, the presence of charge-neutral PEO teeth mitigated deleterious ion interactions, promoting reversible gel-like behavior in cement-PAA/PEO suspensions over a long time scale where pure PAA fails. In cement-PAA/PEO suspensions, hydration phenomena impacted interparticle forces during early stage hydration and, ultimately, led to initial setting through the formation of solid bridges at the contact points between particles within the gelled network.
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign