Compatibility of Slag-Blended Cement with Polycarboxylate Ether Superplasticisers: Rheological Properties Study

The compatibility of slag blended-cement (SBC) with superplasticisers was investigated using rheological measurements. Accordingly, continuous flow tests and thixotropic behaviors were studied for different ages of hydration. In this work, the slag was used in the range of 0-40% in order to substitute the ordinary Portland cement (OPC). Two polycarboxylates ether superplasticisers (PCEs) were used, the acrylic copolymer (PA) and modified polycarboxylate (PC). The saturation point of each superplasticiser was determined on pastes by rheological tests, it is 2% on amount of cement, and the water/cement report is equal to 0.35. The investigation was carried out using a rotational rheometer AR2000 with coaxial cylinders’ geometry. The results showed that the PC-admixture is more efficient than the PA-admixture in OPC; the consistence was consecutively 4.75 Pa.s and 10.45 Pa.s. In addition, the fluidizing effect of the admixtures on cement pastes is conditioned by the presence of slag. The use of PA-admixture in SBC improved rheological properties. However, the use of PC-admixture in SBC increased greatly the viscosity, which involves an incompatibility, the thixotropy increment was from 46898.9 Pa/s (F4) to 59690.1 Pa/s (F9)