An investigation of the rheological parameters of slurry composed of ordinary Portland cement, Portland pozzolana cement and Portland slag cement

Abstract

ABSTRACT This paper compares the rheological parameters of ordinary Portland cement of grade 43 (OPC 43), ordinary Portland cement of grade 53 (OPC 53), Portland pozzolana cement (PPC) and Portland Slag Cement (PSC) to study the thixotropic built. Five slurries with increasing water/cement (w/c) ratios from 0.52 to 0.6 were prepared and examined at resting times of 1 minute, 5 minutes and 10 minutes. Static shear stress (τs), dynamic shear stress (τd) and thixotropic index (β) were studied to analyze the thixotropic built of the slurries. The rheological parameters increase for all the mixes with decreasing w/c ratios and increasing resting times. However, for a w/c ratio greater than 0.60, all the mixes lose their plastic viscosity and the rheological parameters approach non-significant values. The τs and τd values for PPC and PSC pastes are higher than those of the OPC pastes because of the increase in cement fineness and increased rate of structuration and hydration. OPC 53 paste shows high β because of the large extent of reversible thixotropic built. The τs values obtained from the viscometrical tests were then compared the mini slump test values. Results show that the rheological parameters are more consistent than the flow values of the mini slump cone test.