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RESEARCH PRODUCT

Effect of superplasticizers on the rheological properties of fly ash suspensions containing activators of the pozzolanic reaction

subject

description

Rheological studies have been carried out on the effect of a superplasticizer from the sulphonated melamine formaldehyde (SMF) group upon the properties of fly ash suspensions containing a small quantity of mineral admixtures such as cement, lime and gypsum. The superplasticizers' efficiency has appeared to depend greatly on the admixture used. The highest liquefaction degree was found in fly ash suspensions containing both cement and gypsum together and the next it was, when only cement was added. These suspensions exhibit features of a newtonian fluid of low plastic viscosity, when the water to solid ratio (w/s) is 0.3 and a superplasticizer has been used. However, fly ash suspensions with lime, under analogous conditions, produce a considerable increase of the rheological parameters. This may be explained by the effect of the very high specific surface area of hydrated lime upon the consistency of fly ash suspensions.