处理方式对水泥混凝土用钢渣砂体积安定性的影响

Effect of treatment methods on volume stability of steel slag sand for cement and concrete

针对当前天然砂资源日益匮乏的现状,采用炼钢厂的副产品——钢渣作细集料替代天然砂,但钢渣砂的体积安定性一直是制约其应用的关键问题。借助X-射线衍射法、甘油-乙醇法和砂浆棒测长法等测试方法,研究了钢厂内预处理方式(热泼法、自然冷却法)和实验室后期处理方式(自然陈放、8 h蒸汽处理和3 h压蒸处理法)对钢渣砂的膨胀组分含量和砂浆棒膨胀率的影响规律。结果表明:热泼和自然冷却两种预处理钢渣砂的矿物组成相同,各组分的含量不同;经相同时间陈放后,热泼渣安定性的改善程度大于自然渣的;蒸汽和压蒸处理工艺,通过加速钢渣砂中膨胀组分的水化,达到改善其安定性的目的。因此,预处理工艺影响钢渣砂的安定性,提高钢渣砂的安定性需从源头上选择合理的预处理工艺;与蒸汽处理工艺相比,压蒸处理能在短时间内显著改善钢渣砂的安定性。

Using steel slag,a byproduct of steel plant,as fine aggregate aims at the situation of the imbalance between supply and demand of natural sand,but unsoundness hinders its extensive use.It was investigated that the treatment methods including natural cooling,layer pouring,steam and autoclave affected the content of expansive component and linear expansion rate of mortar bar with XRD,glycerol-ethylene glycol method and length measuring.The results indicated that the mineral components of two pretreatment process did not show distinct difference.The soundness improving effcet of layer pouring process was better than natural cooling after one-year aging.Steam and autoclave impoved the volume stability be accelerating the hydration of expansive components.It could be concluded that rational pretreatment radically advaced the volume stability of steel slag and autoclave treatment distinctly enhanced the soundness of steel slag sand in a shorter time compared with steam treatment.