Performance evaluation of nano-silica and silica fume on enhancing acid resistance of cement-based composites for underground structures

硅粉与纳米硅粉水泥基材料的耐酸性

This study aims to evaluate the performance of silica fume(SF)and nano-silica(NS)on enhancing the sulfuric acid resistance of mortar mixtures.The NS and SF were added as substitutions for cement at various dosages.The cured samples were immersed in the sulfuric acid solution with a pH of 2 for 75 d.A compressive strength test and absorption and voids tests were conducted before sulfuric acid immersion.It was found that the addition of SF and NS reduced the volume of permeable voids and increased compressive strength.A thermo-gravimetric analysis was carried out to investigate the hydration of mixtures.The mixtures with SF showed a higher level of pozzolanic reaction compared with mixtures with NS.After the 75 d of immersion,the mixtures with 5%SF and 1%NS showed the best resistance against sulfuric acid because they showed the lowest mass change and length change.

为了研究硅粉与纳米硅粉作为添加剂对水泥砂浆耐酸性的影响,本文将标准养护后的样品浸泡于pH=2的硫酸溶液中,并分析了样品在浸泡实验前后的性能变化。实验结果表明,添加硅粉及纳米硅粉能有效提高浸泡前水泥砂浆的单轴抗压强度,降低可渗透孔隙的体积率。相较于纳米硅粉,硅粉对水泥砂浆的性能影响更为显著。在硫酸溶液中浸泡75 d后,样品出现了不同程度的腐蚀。其中,掺5%硅粉及1%纳米硅粉的样品展现了最低的质量损失及长度损失。