纳米二氧化硅对机制砂混凝土性能的影响研究

Influence of nano-SiO2 on the properties of manufactured sand-based concrete

机制砂在粒形、级配与小于75μm细粒含量方面与天然砂存在明显差异。通过测试抗压强度、动态弹性模量、干缩率考察了纳米二氧化硅对机制砂混凝土性能的影响,借助水化热与界面过渡区测试解释了纳米二氧化硅在机制砂混凝土中的作用机理。结果表明:纳米二氧化硅能一定程度改善机制砂混凝土抗压强度、动态弹性模量与体积稳定性,对混凝土抗冻性能改善作用显著;纳米二氧化硅发生火山灰作用与填充作用,可加速水泥水化,使机制砂混凝土产生更多水化胶凝产物,且显著改善界面过渡区性能。

There are obvious differences between mechanical sand and natural sand in partical size,gradation and fine particle size content less than 75μm.The effects of nano-silica on the properties of mechanical sand concrete were investigated by testing compressive strength,dynamic modulus of elasticity and dry shrinkage,and the mechanism of nano-silica in mechanical sand concrete was explained by heat of hydration and test of interfacial zone.The results show that nano-silica can improve the compressive strength,dynamic modulus of elasticity and volume stability of the mechanical sand concrete to a certain extent,and has a significant effect on the frost resistance of concrete.The pozzolanic reaction and filling effect of nano-silica can accelerate the cement hydration,and it can make the mechanical sand concrete produce more hydration products,and significantly improve property of the interfacial zone.