纳米CaCO_3中间体对水泥基材料性能的影响

Effects of Nano-CaCO_3 Intermediate on Physical and Mechanical Properties of Cement-based Materials

以纳米CaCO3中间体为研究对象。采用凝结时间、力学性能、XRD和SEM测试方法,研究了不同掺量纳米CaCO3中间体对水泥基材料性能的影响,掺量分别为0%、0.5%、1%和2%。结果表明:纳米CaCO3中间体可明显提高水泥抗压强度,掺量1%时,12h、72h和28d龄期的浆体抗压强度分别比基准提高了54%、24%和39%;掺纳米CaCO3中间体后,水泥的需水量变化不大,但凝结时间随掺量的增加而缩短;纳米CaCO3中间体通过晶核作用,细化水化产物晶型,降低孔隙率,改善微观结构,从而提高水泥基材料的抗压强度。

Setting time,mechanical properties and microstructure of cement-based materials containing 0%,0.5%,1% and 2% w/w nano-CaCO3 intermediate,were studied in this paper.The results show that nano particles can significantly increase the compressive strength of cement-based materials.Replaced 1% cement with nano-CaCO3,the compressive strengths of cement-based materials with nano-CaCO3 aged for 12h,72h and 28d are increased by 54%,24% and 39%,respectively,compared with control sample.With increasing the amount of nano particles,water demand changes little,but the setting time reduces obviously.X-ray diffractometry（XRD） and scanning electron microscopy（SEM） results show that the nano particles can be used as crystal nuclei during hydration of cement,then crystal size and porosity of hydration products are reduced,therefore the compressive strength of cement-based material is improved.