Superplasticizer News and Tech > Superplasticizer in concrete > EFFECTS OF DIFFERENT VISCOSITY MODIFYING ADMIXTURES ON RHEOLOGY OF CEMENT PASTE MATRIX OF SELF- CONSOLIDATING

EFFECTS OF DIFFERENT VISCOSITY MODIFYING ADMIXTURES ON RHEOLOGY OF CEMENT PASTE MATRIX OF SELF- CONSOLIDATING

Superplasticizer in concrete 2021-09-03 11:58 108
Better characterization of the rheological properties of water slurry is the first step to study the rheological properties of self consolidating concrete (SCC). The grout must have sufficient fluidity to ensure the fluidity of the SCC itself and sufficient viscosity to support the coarse aggregate. It has been proved that viscosity enhancer (VMA) and appropriate superplasticizer content are very effective in these two characteristics of SCC (high deformation, good segregation resistance and consistency). However, little is known about the interaction between superplasticizer, VMA and paste. The main purpose of this paper is to study the role and impact of VMA. After preparing the self consolidation concrete slurry, the slurry is made of cement containing limestone filler and fly ash. In this study, superplasticizer and VMA with different types and dosage were included. The effects of inorganic VMA (such as micro silica) and organic VMA (based on polysaccharide, starch and cellulose derivatives) combined with superplasticizer on the fluidity and rheology of cement slurry were studied and evaluated. The influence of water cement ratio (w / C) on the early hydration of cement slurry and the development of mortar strength is also the focus of this study. Paste measurements are based on empirical tests, i.e. minimum slump and rheometer. When the ratio of water to binder is constant, the increase of viscosity regulator (VMA) will reduce the flow, and the yield stress and plastic viscosity will also increase. It was found that polysaccharide based VMA was the most effective one. The yield stress of cement slurry changes with time due to hydration reaction. The hydration of cement was monitored by isothermal calorimetry and thermogravimetry (TGA). Organic VMA has little effect on the development of early cement hydration and compressive strength. However, inorganic VMA will accelerate the hydration of cement and higher compressive strength within the service life of 1 day. Expand ▼
Tag:EFFECTS,DIFFERENT,VISCOSITY,MO