Research on the effect of apparent density on the rheological properties of lightweight and heavyweight concrete

This paper investigated the influence from apparent density on rheological property of lightweight and heavyweight concrete. The apparent densities of 1761 kg/m³, 3048 kg/m³ and 3548 kg/m³ were selected. The obtained results showed when the slump for lightweight and heavyweight concrete was controlled in the range of 160 ± 10 mm, the yield stress (τ0) and plastic viscosity (μp) increased significantly as the addition of the apparent density. The slump tests of fresh lightweight and heavyweight concrete were numerically simulated with an error of less than 3.0 % using lattice Boltzmann method (LBM). The established slump model could accurately predict the flow behavior and characteristics of lightweight and heavyweight concrete at different apparent densities. By comparing the distribution of physical fields such as velocity and pressure, the effect of apparent density upon the flow behavior of lightweight/heavyweight concrete was analyzed in depth, and the changing rule in rheological performance of concrete with different apparent densities was clarified. •The yield stress and plastic viscosity of lightweight/heavyweight concrete increased with increasing apparent density ρ.•The slump test model is effective in predicting the flow behavior of lightweight/heavyweight concrete at different ρ.•There was an obvious positive correlation between ρ and the pressure exerted on the bottom concrete.•The apparent viscosity of lightweight/heavyweight concrete rose with the growth of ρ when controlling for the same slump.