纳米SiO2-矿渣-水泥复合胶凝材料的抗硫酸盐侵蚀试验

Experimental Study on Sulfate Attack Resistance of Nano SiO2-Slag-Cement Composite Cementitious Material

为研究纳米二氧化硅-矿渣-水泥复合胶凝材料的抗硫酸盐侵蚀性能,将砂浆试件浸泡在不同温度下的3%硫酸钠溶液中进行侵蚀试验,以抗折强度和抗蚀系数作为指标对其抗蚀性进行评价,并与普通硅酸盐水泥和抗硫酸盐水泥试件进行对比。采用微观分析方法对腐蚀产物的成分进行分析。研究结果表明:纳米二氧化硅-矿渣-水泥复合胶凝材料在不同温度下均具有优异的抗硫酸盐侵蚀能力,随着纳米二氧化硅掺量的增加,抗蚀性能增强;随着温度的降低,试件的侵蚀速率加快,270d的抗蚀系数及抗折强度逐渐降低。养护温度的改变导致腐蚀产物的成分发生变化,5℃养护条件下腐蚀产物中钙矾石及碳硫硅钙石均存在,但以后者为主。

In order to study the corrosion resistance of nano silica slag cement composite cementitious material,the erosion tests of mortar specimens were conducted with 3%solution of sodium sulfate at different temperatures.The flexural strength and corrosion resistance coefficient were introduced to evaluate the corrosion resistance of specimens,and the results were compared with specimens made of common portland cement and the sulfate resistant cement.Moreover,conventional microscopic instruments were used to investigate the components of corrosion products during erosion tests.The results show that nano silica slag cement composite cementitious material has excellent anticorrosion to sulfate solution at different temperatures.It is found that the corrosion resistance increases with the increase of nano silica content.Besides,with the decline of the temperature,the corrosion rate increases,while the corrosion resistance coefficient and flexural strength of the specimen at 270d decrease gradually.Furthermore,the change of the curing temperature results in changes of the components of the corrosion products,the ettringite and thaumasite appeare in the corrosion products at 5℃,of which the thaumasite is the dominant component.