摘要
为了消除钢渣微粉(steel slag,SS)中的游离氧化钙和氧化铁,激发SS的胶凝性能,以NH_(4)H_(2)PO_(4)为激发剂对SS进行活性激发,研究了不同养护条件下,NH_(4)H_(2)PO_(4)掺量对其激发SS浆体工作性能、体积稳定性、力学性能的影响规律,结合X射线衍射(X-ray diffraction,XRD)和扫描电子显微镜(scanning electron microscope,SEM)分析探讨了NH_(4)H_(2)PO_(4)激发SS反应产物的种类及微观结构。结果表明:随m(NH_(4)H_(2)PO_(4))/m(SS)的增加,浆体的凝结时间延长;室温养护条件下,m(NH_(4)H_(2)PO_(4))/m(SS)>0.2时,浆体会发生膨胀,当m(NH_(4)H_(2)PO_(4))/m(SS)=0.6时,膨胀率约40%。加压养护可以有效避免浆体的膨胀,在室温环境下,试样28 d的抗压强度可达5.5 MPa,快速养护对硬化浆体的抗压强度影响不大。XRD和SEM分析结果显示:SS经NH_(4)H_(2)PO_(4)激发后,所得反应产物主要为Ca(NH_(4))_(2)(HPO_(4))_(2)·H_(2)O、Ca_(3)(PO_(4))_(2)和FePO_(4);加压养护使反应产物填充于狭小微观空间里,增加基体密实度。
In this investigation,steel slag(SS)was activated by using NH_(4)H_(2)PO_(4)as an activator to eliminate free calcium oxide and iron oxide in SS powder and to excite the cementitious properties of SS.The effects of NH4H2PO4 content on the working performance,volume stability and mechanical properties of SS slurry activated by NH_(4)H_(2)PO_(4)4H2PO4 under different curing conditions were studied.The types and microstructure of reaction products of SS activated by NH_(4)H_(2)PO_(4)were characterized by XRD and SEM.Results show that the setting time of slurry prolonged with the increase of the mass ratio of NH_(4)H_(2)PO_(4)to SS.Slurry will expand under room temperature curing conditions,when the mass ratio of NH_(4)H_(2)PO_(4)to SS is greater than 0.2,and the expansion rate reaches about 40%when the mass ratio is 0.6.The expansion of slurry can be effectively avoided using pressure curing.The compressive strength of the sample after 28 days reaches 5.6 MPa at room temperature while rapid curing has little effect on the compressive strength of hardened slurry.XRD and SEM results show that the reaction products of SS activited by NH_(4)H_(2)PO_(4)were mainly Ca(NH_(4))_(2)(HPO_(4))(2)·H_(2)O,Ca_(3)(PO_(4))_(2)and FePO_(4).The reaction products fill in a narrow micro space and the density of the matrix increases under pressure curing.
作者
李悦
龙世儒
林辉
LI Yue;LONG Shiru;LIN Hui(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)
出处
《北京工业大学学报》
CAS
CSCD
北大核心
2023年第7期769-775,共7页
Journal of Beijing University of Technology
基金
北京市自然科学基金资助项目(8202005)
国家自然科学基金资助项目(52078015)。
