The Performance Of Different Types Of Superplasticizer

High performance concrete is a good example of the application of high performance cement-based materials. Superplasticizer has played the vital roles in the high performance of concrete. The systematical study on the rheological characteristics,hydration exothermic reaction,electrical property,early microstructure and shrinkage performance of the fresh cement paste with different superplasticizers were conducted in order to analyze the impact of superplasticizer to the hydration process of cement, by researching the different property of fresh cement with superplasticizer.Stirring viscosimeter is employed to research the rheological property of fresh cement paste with different superplasticizers. Mapping rheogram and analyzing thixotropy of fresh cement paste with different superplasticizers by measuring the rheologic parameters such as shearing stress,yield stress and plastic viscosity.Using multi-channel isothermal calorimeter together with non-contacting electrical resistivity device, traditional hydration heat testingl and electrical resistivity testing were connected. Using temperature-sensitive of traditional hydration heat model and structure-sensitive of structure formation model, instantaneous formation condition of paste structure was described exactly. Regulative action of superplasticizers to hydration process were studied systematically. In addition, impact of superplasticizers to hydration procee were discussed thoroughly.Results showed that superplasticizers improved cement hydration process.Initial hydration of cement was accelerated by superplasticizers because of their high range water reducing and dispersive action.After that, hydration rate was descended as a result of more initial hydrates and absorption of superplasticizers. Dense of structure and development of final properties were benefited from retardation of hydration.In contrast, cement hydration process was controlled better by polycarboxylate superplasticizer than the other three superplasticizers owing to its stereoscopic action.And its adaptability to cement was better,by which the cement particles were...