Prediction of the rheological properties of nanosilica blended self-compacting concrete under the influence of a dispersing agent

Abstract

The effect of nanosilica under the influence of dispersing agents on the fresh empirical and fundamental rheological properties of self-compacting concrete (SCC) is a complex phenomenon which has been investigated in this paper. Models to predict the rheological properties of nanosilica blended SCC are also lacking to avoiding/saving comprehensive and costly rheology laboratory trials mainly when these tests are unavailable or limited. To these ends, 315 laboratory tests were performed on 15 blended SCC mixtures, manufactured using five nanosilica dosages, 0%, 0.5%, 1%, 1.5%, 2%, and three dispersing superplasticizer dosages, 0.62%, 0.66%, 0.70%, by weight of cement. Fundamental rheological properties of the SCC mixes were assessed by using a rotational concrete rheometer based on the nonlinear modified Binghamian model. Results showed that SCC mixes are sensitive to nanosilica and superplasticizer admixtures producing a complex non-linear effect on their empirical and rheological properties. Based on these trends, eleven empirical models were proposed to predict the fresh empirical and rheological properties of the SCC mixes. A statistical analysis demonstrated the good fitting of the proposed models with the measured properties of SCC mixes during the laboratory trials. These models could serve for design and production of nanosilica blended SCC as alternative approach.