电解锰渣改性聚合物磷酸镁水泥复合材料早期微细观孔结构分析
Analysis of early microscopic pore structure of electrolytic manganese residue modified polymer magnesium phosphate cement composites
杨天霞 1乔宏霞 2栾帅 1路承功 1张磊1
作者信息
- 1. 兰州理工大学 土木工程学院,甘肃省先进土木工程材料工程研究中心,兰州 730050
- 2. 兰州理工大学 土木工程学院,甘肃省先进土木工程材料工程研究中心,兰州 730050;中国科学院盐湖资源综合高效利用重点实验室,西宁 810000;青海民族大学 土木与交通工程学院,西宁 810000
- 折叠
摘要
利用电解锰渣(Electrolytic manganese residue,EMR)可减缓聚合物磷酸镁水泥复合材料水化速率、延长凝结时间、改善微细观结构等特点,通过宏观物理力学性能、工作性能,结合微观手段XRD、SEM、TG-DTG及NMR等测试手段研究EMR掺量对聚合物磷酸镁水泥早期宏观和微细观孔隙结构性能影响机制.结果表明:加入EMR后能够改善浆体的工作性能,提升后期强度并有效细化孔隙结构;掺加 2wt％EMR的28 d抗压强度值达到 49.5 MPa,3wt％、4wt％掺量强度明显降低;水化产物除了长细条树状鸟粪石(Struvite,MgKPO4·6H2O&MgNH4PO4·6H2O)和原料中片块状MgO外,Mn元素参与反应形成含锰化合物,水化产物相互搭接形成致密微细观结构细化了孔隙;TG-DTG曲线中在 100℃出现明显的吸热峰对应鸟粪石的吸热脱水现象,质量损失率为 13.299wt％;掺加EMR的试件出现 3个吸热峰,包括Mn(OH)2 和Mn3(PO4)2·3H2O失去结合水的过程;核磁共振弛豫时间T2 谱弛豫时间会滞后,孔径在过渡孔和毛细孔的分布范围较大,总孔隙度随掺量增大而降低,渗透率先减小后增大,1wt％和 2wt％掺量的复合材料主要以凝胶孔和过渡孔分布,大孔分布面积较少,内部结构较密实,渗透率低,束缚流体饱和度高,自由流体饱和度较低.
Abstract
Electrolytic manganese residue(EMR)can slow down the hydration rate of polymer magnesium phos-phate cement composite mortar,prolong the setting time and improve the microstructure.Through macroscopic physical and mechanical properties,working performance,combined with microscopic means such as XRD,SEM,TG-DTG and NMR techniques were used to investigate the mechanism of the influence of EMR dosage on the early macroscopic and microscopic pore structure properties of magnesium phosphate cement.The results show that the addition of EMR can improve the working performance of the slurry,enhance the later strength and effectively re-fine the pore structure.The 28 d compressive strength value of adding 2wt％EMR reaches 49.5 MPa,and the strength of 3wt％and 4wt％additives is significantly reduced.In addition to the elongated tree like struvite(MgKPO4·6H2O)and block like MgO in the raw material,Mn elements participate in the reaction to form manganese containing compounds,and the hydration products overlap with each other to form a dense microstructure which refines the pores.TG-DTG curve at 100℃appeared obvious heat-absorption peak corresponds to the heat-absorption dehydra-tion phenomenon of guano stone,the mass loss rate is 13.299wt％.EMR-doped specimens appeared three heat-ab-sorption peaks,including the process of the loss of bound water by Mn(OH)2 and Mn3(PO4)2·3H2O.NMR relaxation time T2 spectra will be lagging behind,the pore size in the range of the transition pores and the distribution of the capillary pores.The total porosity decreases with the increase of doping,and the permeability decreases first and then increases.The pores of composites with 1wt％and 2wt％doping are mainly distributed by gel pores and tran-sition pores,the distribution area of macropores is less,the internal structure is more dense,and the permeability is low,the saturation of bound fluid is high,and the saturation of free fluid is low.
关键词
聚合物磷酸镁水泥复合材料/工作性能/力学性能/同步热分析/T2谱/微细观孔隙结构Key words
polymer magnesium phosphate cement composite mortar/working performance/mechanical pro-perties/synchronous thermal analysis/T2 spectrum/microscopic pore structure引用本文复制引用
出版年
2024
NETL
NSTL
万方数据