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

作　　者：杨天霞 乔宏霞[1,2,3] 栾帅 路承功 张磊 YANG Tianxia;QIAO Hongxia;LUAN Shuai;LU Chenggong;ZHANG Lei(Gansu Advanced Civil Engineering Materials Engineering Research Center,School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Chinese Academy of Sciences,Xining 810000,China;School of Civil and Traffic Engineering,Qinghai Minzu University,Xining 810000,China)

机构地区：[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]中国科学院盐湖资源综合高效利用重点实验室,西宁810000 [3]青海民族大学土木与交通工程学院,西宁810000

出　　处：《复合材料学报》2024年第12期6811-6825,共15页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(51868044,52178216);青海省基础研究计划项目(2022-ZJ-921);甘肃省优秀研究生“创新之星”项目(2022CXZX-450);兰州理工大学红柳一流学科建设计划,甘肃省交通运输厅科技项目(2022-23)。

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49.5MPa,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,MgKPO_(4)·6H_(2)O&MgNH_(4)PO_(4)·6H_(2)O)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Mn_(3)(PO_(4))_(2)·3H_(2)O失去结合水的过程;核磁共振弛豫时间T_(2)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。Electrolytic manganese residue(EMR) can slow down the hydration rate of polymer magnesium phosphate 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 refine the pore structure.The 28 d compressive strength value of adding 2wt%EMR reaches 49.5 MP a,and the strength of 3wt% and 4wt% additives is significantly reduced.In addition to the elongated tree like struvite(MgKPO_(4)·6H_(2)O)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 dehydration phenomenon of guano stone,the mass loss rate is 13.299wt%.EMR-doped specimens appeared three heat-absorption peaks,including the process of the loss of bound water by Mn(OH)_(2) and Mn_(3)(PO_(4))_(2)·3H_(2)O.NMR relaxation time T_(2) 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 lwt% and 2wt% doping are mainly distributed by gel pores and transition 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 T_(2)谱 微细观孔隙结构 

分 类 号：TU599[建筑科学—建筑技术科学] TB332[一般工业技术—材料科学与工程]