Abstract

In calcium aluminate cements (CAC), it is recommended to work with low water/cement ratios (for example using superplasticizers admixtures) to avoid the negative effects of metastable hexagonal hydrate conversion to stable cubic ones. The present work studies the compatibility between CAC and three polycarboxylate ether (PCE) admixtures with different structures. The C/E ratio of PCE admixtures was less important to the adsorption values in CAC suspensions than those of Portland-based binder (OPC). The more positive zeta potential in the CAC pastes may be the reason why these admixtures (regardless of their C/E ratio) adsorb onto cement particles with a different conformation than observed in OPC pastes. The presence of PCE admixtures decreases yield stress of CAC pastes at a lower dosage than that needed for OPC pastes. However, after 15 min CAC pastes with PCE admixtures lose their fluidity, an indication of the scant compatibility between these materials.