Creep performance of high stone powder manufactured sand concrete

To explore the mechanical and long-term deformation properties of high stone powder manufactured sand concrete, this study takes water-to-binder ratios (0.37, 0.45) and stone powder contents (6%–30%) as variables, and carries out strength and creep tests based on 378 specimens. The results show that the stone powder content has an influence law of "first increasing and then decreasing" on concrete strength; the optimal ranges of stone powder content are 15%–20% under the water-to-binder ratio of 0.37 and 10%–15% under the water-to-binder ratio of 0.45, respectively. The stone powder exhibits a nonlinear bidirectional regulatory effect on creep: either too high or too low stone powder content will increase creep, and the critical stone powder contents corresponding to the minimum creep are 18% under the water-to-binder ratio of 0.37 and 15% under the water-to-binder ratio of 0.45. Based on the CEB-FIP MC2010 model, a creep prediction model for high stone powder manufactured sand concrete is established by introducing the stone powder content correction factor. This model can accurately reflect the critical effect of 15% stone powder content and the variation trends of creep for N15 and N30; compared with the original model, its mean absolute error and relative error are reduced by 41.7%–53.2%, which provides a reliable prediction method for the engineering application of high stone powder manufactured sand concrete.