关键词: 纳米SiO2;聚羧酸减水剂;吸附作用;分散性;流动性

Abstract: The adsorption effect of nano-SiO2 on superplasticizer were studied by using the infrared spectroscopy,ultraviolet-visible spectrophotometer,and zetasizer nano was used to study the effect of superplasticizer on the dispersion of nano-SiO2 and the fluidity of the paste.The research results show that polycarboxylate superplasticizer is adsorbed by nano-SiO2 and the adsorption amount increase with the increasing of the concentration of the superplasticizer,when the concentration of the superplasticizer increased to 5 g/L,the adsorption amount approach saturation.With the addition of superplasticizer,the dispersion of nano-SiO2 is greatly reduced,the particle size of the nano-SiO2 increase and the particle size distribution curve shift to the larger particles.The nano-SiO2 is dissolved in the mixed water firstly,next mixing with cement,and then adding water reducing agent,which can reduce the adsorption of nano-SiO2 to water superplasticizer,increase the utilization efficiency of superplasticizer,and improve the fluidity of cement paste.

Key words: nano-SiO2;polycarboxylate superplasticizer;adsorption;fluidity;dispersion