Influence of cationic polymer on the floccule size of cement pastes containing polycarboxylate superplasticizer and Na-bentonite

Influence of cationic polymer (KN) on the floccule size of cement pastes containing plycarboxylate superplasticizer (PCE) and Na-bentonite was studied. The proportion of floccule size and grain size d(f)/d(g) was obtained from a rheological analysis with the application of Herschel-Bulkley model and modified Krieger-Dougherty model. Herschel-Bulkley model was used to gain the yield stress according to our previous study. Cement pastes were investigated both at the beginning and after one hour. The results showed that a high value of d(f)/d(g) was noticed under low shear rate range and then the proportion decreased with the increase of shear rate. For cement paste containing PCE and Na-bentonite in the absence of KN, larger floccule was formed due to the intercalation of polyethylene glycol branch chain of PCE into the interlayer space of Na-bentonite. However, the floccule size of cement pastes obviously decreased with the increasing addition amount of KN. Thus, KN will restrain the formation of floccules in cement pastes containing PCE and Na-bentonite to a certain extent.