Evaluation of rheological parameters of mortar containing various amounts of mineral addition with polycarboxylate superplasticizer

• Natural pozzolan decreases slump of mortars and needs more superplasticizer dosage.
• Slag and limestone powder increase the workability at 10% of replacement rate.
• BFS and LP decrease the viscosity of mortars even without superplasticizer.
• The new relationship predicts the rheological parameters with a high correlation.

The presented study explores the effect of limestone powder (LP), finely blast furnace slag (BFS) and natural pozzolan (NP) on mortar rheology and the interaction of these additions with polycarboxylic-based superplasticizer (PC). It was found that LP and BFS are more effective than NP. The viscosity and yield stress of mortar are obviously decreased with increasing dosage of PC. PC superplasticizer loses its positive effect where NP is added and becomes more effective with LP and BSF. Mathematical relationship is proposed to express the variation of each rheological parameter which provides a more convenient prediction with an acceptable accuracy.