微生物提升钢渣胶凝材料安定性和强度的作用及机理

Effect and Mechanism of Microorganism to Improve the Stability and Strength of Steel Slag Cementitious Material

目前钢渣排放量、库存量大,但利用率不高,关键是安定性未能解决。本文研究提出了通过微生物矿化技术提升安定性和强度,研究了不同掺量微生物对钢渣中主要矿物相碳化反应速率的影响,测试了微生物掺量和钢渣粉比表面积对试件压蒸线性膨胀率和强度的影响,通过MIP和SEM分析试件孔隙率和微观形貌,并对微生物改性钢渣胶凝材料机理进行分析。结果表明,微生物能提高钢渣中游离氧化物和硅酸盐矿物相碳化反应速率,提高矿化产物的强度。要使试样压蒸线性膨胀率降低至0.5‰以下,采用微生物添加剂后,试验所用钢渣粉比表面积可由565 m^2/kg降低至360 m^2/kg。钢渣中掺入微生物可促进碳化过程中矿物相离子溶出和碳酸盐矿物生成,降低试件孔隙率,密实基体结构,从而提高钢渣胶凝材料试件的强度。微生物-钢渣胶凝材料制品强度可达40 MPa以上,其他物理性能均符合国家标准,在实际道路铺装工程应用中体积稳定性好,无泛碱现象,且利润优势显著,应用前景广阔。

At present,the discharge and inventory of steel slag are large,however the utilization rate is poor because the problem of stability has not been solved well.In this paper,it was proposed to improve the stability and strength of steel slag through microbial mineralization technology.The effects of microorganism content on the carbonation reaction rate of main mineral phase in steel slag were studied.The effect of microorganism content and specific surface area of steel slag powder on the linear expansion rate and strength of autoclaved steel slag samples was tested.The porosity and microstructure of steel slag samples were analyzed by MIP and SEM,and the mechanism of cementitious material modified by microorganism was analyzed.The results show that microorganism improves the carbonation reaction rate of free oxide and silicate mineral phase in steel slag,and increases the strength of mineralized products.To reduce the autoclave linear expansion rate of samples to less than 0.5‰,the specific surface area of steel slag powder is reduced from 565 m^2/kg to 360 m^2/kg with microorganism additive.The incorporation of microorganism into the steel slag promotes the ions dissolution of mineral phase and the formation of carbonate minerals,reduces the porosity of the test piece and compacts the matrix structure,so as to improve the strength of the steel slag cementitious material samples.The strength of microorganism-steel slag cementitious material products reaches more than 40 MPa,and other physical properties meet the Chinese standards.In the actual application of road pavement engineering,the volume stability is good.And there is no efflorescence phenomenon,the profit advantage is significant,and the application prospect is broad.