Optimization of Mix Proportion of Self-compacting Concrete Based on Single Fluid Model

The study aims to optimize the mix proportion of self-compacting concrete according to the workability and compressive strength. Firstly, based on computational fluid dynamics, the flowability and filling ability of self-compacting concrete were simulated by the single-fluid model to verify the single-fluid model. And then, the simulation of casting a pre-cambered composite beam was carried out. In the end, the mix proportion was optimized considering the filling ability and the compressive strength of self-compacting concrete. The results showed that increasing sand rate can improve the workability and decrease the rheological parameters of self-compacting concrete. The mixture with a 45% sand ratio in the case of 3% silica fume alone or 43% sand ratio in the case of 30% granulated blast furnace slag and 3% silica fume had adequate filling ability and excellent long term compressive strength. Moreover, the model can be used to simulate the filling ability and passing capacity of self-compacting concrete and the maximum error between the simulation results and the actual measured value is 4.80%. When the concrete mixture is considered to be uniform, namely, without considering the effect of the aggregates, the single-fluid model can simulate the casting of self-compacting concrete.