铁路工程预应力结构用机制砂混凝土性能研究

Study on Performance of Manufactured Sand Concrete for Prestressed Structures in Railway Engineering

以梁体和轨道板用混凝土为研究对象,从工作性能、力学性能、耐久性能、收缩徐变性能等多方面对比研究了铁路工程预应力结构用机制砂混凝土和河砂混凝土的性能差异。结果表明:机制砂混凝土需掺加更多的减水剂和引气剂来达到与河砂混凝土相同的工作状态;石灰石粉的促进水化作用和机制砂的颗粒特性提高了机制砂混凝土早期抗压强度、抗折强度和弹性模量;石灰石粉的填充效应有利于提高混凝土密实度,降低混凝土离子扩散系数和电通量;机制砂混凝土抗冻性能满足梁体和轨道板的技术要求;机制砂混凝土收缩徐变的变化规律与河砂混凝土一致。

Taking concrete used for beam and track slab as research object,the performance differences between manufactured sand concrete and river sand concrete for prestressed structures in railway engineering were contrastively studied from the aspects of workability,mechanical property,durability,shrinkage and creep.The results show that more superplasticizer and air-entraining agent should be added to manufactured sand concrete to achieve the same workability as river sand concrete.The early compressive strength,bending strength and elasticity modulus of the manufactured sand concrete are improved due to the hydration promotion effect of limestone powder and the particle effect of manufactured sand.The f illing effect of limestone powder is conducive to improving the compactness of concrete and reducing the ion diffusion coeff icient and electric f lux of concrete.The frost resistance of manufactured sand concrete meets the technical requirements of beam and track slab.The change rule of shrinkage and creep of the manufactured sand concrete is consistent with that of the river sand concrete.