道路基层复合胶凝材料的性能调控

研究了熟料钢渣粉煤灰磷石膏系道路基层复合胶凝材料的凝结时间、胶砂强度和膨胀性能的调控,分析了其缓凝微膨胀机理.结果表明：磷石膏中的可溶性杂质会与Ca2+和OH-反应,生成难溶物覆盖在胶凝材料颗粒表面,显著延长凝结时间,磷石膏掺量每增加3%,即可延长凝结时间约65min;大掺量磷石膏可为浆体提供充足的SO2-4,保证钙矾石的大量稳定生成,使硬化浆体产生微膨胀;过量磷石膏亦会造成过大的膨胀,破坏硬化浆体结构,通过加入适量钢渣取代粉煤灰,可以促进复合胶凝材料的早期水化，优化孔结构,明显提高道路基层复合胶凝材料的性能.

Performance Regulation of Road Base Composite Binder

The setting time, strength and expansion properties of clinker steel slag fly ash phosphogypsum series road base composite binder were studied. The results show that the soluble impurities in phosphogypsum can react with Ca2+ and OH- to form insoluble substances covering the surface of binder particles, which significantly extends the setting time, the setting time can be prolonged about 65min with a 3% increase in the content of phosphogypsum.At the same time, large amount of phosphogypsum can provide sufficient SO2-4 ions for the slurry to ensure the large amount of stable formation of ettringite,and makes the hardened slurry slightly expand.However, excessive amount of phosphogypsum will also cause excessive expansion and leads to structural damage.The early hydration of composite binder and the optimization of pore structure can be promoted by adding appropriate amount of steel slag instead of fly ash,and the performance of road base composite binder can be significantly improved.