The influence of specific surface and mineral composition of cement on rheology of fresh superplasticized mortars

The results of the investigation into the influence of cements different in physicochemical properties on rheological properties of fresh mortars with different superplasticizers are presented and discussed. Rheology results have been evaluated according to the Bingham model, which describes the rheology with the two parameters: yield value and plastic viscosity. On the base of statistical analysis of obtained results it was found that rheological properties of superplasticized mortars depends successively on: C(3)A content in cement, specific surface of cement, Na2Oe content in cement and interaction of these factors. The basic trends of influence of specific surface of cement, CA Na2Oe and SO3 content in cement on rheology of mortars with different superplasticizers are presented and discussed. On the base of obtained results a simple mathematical model of influence of specific surface of cement, C(3)A Na2Oe and SO3 content in cement on rheological parameters of mortars with and without superplasticizers were developed. It is concluded that worked out model can be used for assessment compatibility of cement - superplasticizer system. Presented in paper basic relationships of influence of cement properties on rheological properties of mortars can be applied for designing and controlling workability of fresh mortars and concretes.