机制砂石粉含量及MB值对高强混凝土性能的影响

研究了机制砂石粉含量及MB值对高强混凝土性能的影响。结果表明，适量的石粉可在一定程度上弥补机制砂表面的粗糙，改善新拌混凝土的工作性；当石粉含量较高时，由于石粉对外加剂及游离水的吸附作用，新拌混凝土工作性能逐渐劣化。随着石粉含量增大，混凝土抗压强度下降，劈裂抗拉强度和弹性模量呈先增后降趋势。本试验中机制砂中石粉的最佳含量为3%～6%。随着MB值增大，新拌混凝土工作性能快速劣化，混凝土的抗压强度和劈裂抗拉强度呈下降趋势；当MB值<1.1时，随着MB值增大，混凝土的弹性模量未有明显变化，当MB值≥1.1时，混凝土的弹性模量快速下降。本试验中机制砂的最佳MB值应小于0.75。

Influence of manufactured sand with different stone powder contents and MB values on properties of high-strength concrete

Influence of manufactured sand with deferent stone powder contents and MB values on properties of high-strength concrete is studied. The results show that the proper amount of stone powder can make up the roughness of the surface of manufactured sand, and improve the workability of fresh concrete. When the content of stone powder is higher, the workability of fresh concrete gradually deteriorates due to the adsorption of stone powder on additives and free water. With the increasing of stone powder content, the corresponding concrete compressive strength decreases, and the splitting tensile strength and elastic modulus increase first and then decrease. In this experiment, the optimum value of stone powder in manufactured sand is 3%~6%. With the increasing of MB value, the workability of fresh concrete deteriorates rapidly, and the compressive strength and splitting tension of concrete decrease. When the MB value is lower than 1.1, the elastic modulus of concrete has no obvious change with the increasing of MB value. When the MB value is higher than 1.1, the elastic modulus decreases rapidly. In this experiment, the optimum MB value of manufactured sand should be lower than 0.75.