三种不同掺合料对水泥浆体界面性能的影响

Effect of three different admixtures on interfacial properties of cement paste

为了分析新型矿物掺合料对高性能混凝土界面区微结构的影响,采用层析方法进行研究。通过分别掺入不同量的钢渣、矿渣及粉煤灰,定量分析了硅酸盐水泥浆体-集料界面区氢氧化钙取向指数和界面区厚度的变化。试验结果表明:(1)掺入30%矿渣粉后,界面处Ca(OH)_2取向比纯水泥明显下降,几乎没有取向,界面区厚度比纯水泥浆体的界面略低。掺30%粉煤灰后,界面处Ca(OH)_2取向度介于纯水泥与掺矿渣粉水泥界面取向度之间,但过渡区厚度明显减小。加入30%的钢渣后,水泥浆体与集料的界面晶体取向明显增加,界面区厚度也明显增加;(2)随钢渣比表面积增加,水泥浆体与集料界面的Ca(OH)_2晶体取向度及界面厚度都有不同程度的减小。当钢渣比表面积增加至600 m^2/kg时,含钢渣浆体界面的性能已优于纯水泥浆体界面的性能;(3)钢渣与矿渣粉或粉煤灰二元复合只能改善浆体与集料界面区某一方面的性能,但钢渣与矿渣粉、粉煤灰三元复合可明显改善浆体与集料界面的综合性能。研究结果可为高性能混凝土整体性能研究及设计提供参考意见。

In order to analyze the influence of new mineral admixtures on the microstructure of high-performance concrete interface zone, the chromatographic test method is used to study the incorporation of different amounts of steel slag, slag and fly ash to the Portland cement slurry-aggregate interface hydrogen, and the influence of the calcium oxide orientation index and the thickness of the interface region is analyzed. The test results show that:(1) After the addition of 30% slag powder, the Ca(OH)2 orientation at the interface is significantly lower than that of pure cement, and there is almost no orientation. The interface zone thickness is slightly lower than that of the pure cement slurry. After adding 30% fly ash, the degree of Ca(OH)2 orientation at the interface is between the interface degree of pure cement and slag-mixed cement, but the thickness of the transition zone is significantly reduced. After adding 30% steel slag, the interfacial crystal orientation of the cement paste and the aggregate increase significantly, and the thickness of the interface zone also increases significantly.(2) The Ca(OH)2 crystal at the interface between the cement paste and the aggregate decrease with the increase of the specific surface area of the steel slag. The degree of orientation and the same thickness are reduced to varying degrees. When the specific surface area of steel slag is increased to 600 m2/kg, the performance of the interface containing steel slag slurry is better than that of pure cement slurry interface;(3)The binary compound of steel slag and slag powder or fly ash can only improve the slurry and set. The performance of a certain aspect of the interface area, but the combination of steel slag and slag powder and fly ash can significantly improve the comprehensive performance of the slurry and aggregate interface. The research results can provide reference for the research and design of high performance concrete performance.