混掺固废磷石膏纤维增强水泥基复合材料强度特性与机制  

Strength characteristics and mechanism of cementitious composites reinforced by fibers of mixed solid waste phosphogypsum

作　　者：付军[1,2] 张澳 赵洲峰 裘吕超 李锐杰 朱哲汛 FU Jun;ZHANG Ao;ZHAO Zhoufeng;QIU Lyuchao;LI Ruijie;ZHU Zhexun(School of Transportation&Shipping,Wuhan University of Technology,Wuhan 430063,China;State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China;State Grid Zhejiang Electric Power Comporation Research Institute,Hangzhou 310014,China)

机构地区：[1]武汉理工大学交通与船海工程学部,武汉430063 [2]武汉理工大学硅酸盐建筑材料国家重点实验室,武汉430070 [3]国网浙江省电力有限公司电力科学研究院,杭州310014

出　　处：《复合材料学报》2024年第9期5070-5082,共13页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(52378235);国家电网企业发展基金(GJRD2022-04)。

摘　　要：采用流浆法成功制备了一种混掺磷石膏固废的纤维增强水泥复合材料。首先对固废磷石膏进行生石灰中和、去杂、烘焙改性处理激发其胶凝特性,再按质量比5∶4∶1比例与矿粉、钢砂混合,形成改性固废磷石膏混合料(Modified solid waste phosphogypsum mix,MWPM)作为辅助胶凝材料,取代部分水泥;采用固废磷石膏集料替代部分天然细集料,同时考虑掺入少量聚甲醛(POM)纤维及木制纸浆纤维,进行纤维增强水泥基复合材料的基准配合比设计研究,并结合XRD及SEM分析其强度及微观机制。结果表明:MWPM与磷石膏集料的掺量对固废纤维增强水泥板的密度、吸水率、导热系数等几乎没有影响;尽管前期强度随着MWPM掺量的增加而略微降低,但在掺量达到18wt%左右时仍能保持在4 MPa左右,且后期强度相比之下有部分增强;同时经过冻融实验后的冻融抗折强度比率不低于70%,满足非承重纤维增强水泥板规范需求;磷石膏集料对复合材料有微小的增强效应,掺量为20wt%时相对优化。基于上述研究,提出了混掺磷石膏固废纤维增强水泥基复合材料的基准配合比,可有效利用固废磷石膏155.39 kg/m^(3),减少水泥消耗78.58 kg/m^(3),降低CO_(2)排放27.60 kg/m^(3)。微观分析表明:二水磷石膏、钙矾石和水化硅酸钙凝胶相互填充结合,形成互穿三维空间结构,同时通过引入POM纤维和木质纸浆纤维,使基体、骨料与两种纤维形成了更紧密的整体结构,这种结构的形成可进一步提高试件的整体力学性能。混掺磷石膏固废纤维增强水泥复合材料兼具良好力学性能和固废利用率,可为非承重绿色保温材料的发展提供参考。The fiber reinforced cement composite blended with phosphogypsum solid waste was successfully prepared using the flow slurry method.Firstly,the solid waste phosphogypsum was neutralized with quicklime,decontaminated and baked to stimulate its cementitious properties,and then mixed with mineral powder and steel sand in the ratio of 5∶4∶1 to form modified solid waste phosphogypsum mix(MWPM)to replace part of the cement as an auxiliary cementitious material.At the same time,solid waste phosphogypsum aggregate was used to replace part of the natural fine aggregate,while a small amount of polyoxymethylene(POM)fibers and wood pulp fibers were considered to be incorporated to carry out a baseline proportion design study of fiber-reinforced cementitious composites and to analyses their strength and micro-mechanisms in combination with XRD and SEM.The results show that the dosage of MWPM with phosphogypsum aggregate has almost no effect on the density,water absorption,thermal conductivity,etc.of solid waste fiber-reinforced cement boards;Although the strength in the early stage decreases slightly with the increase in the dosage of MWPM,it can still be maintained at about 4 MPa when the dosage reaches about 18%,and the strength in the later stage is partially enhanced compared to that of MWPM,while the ratio of flexural strength is not less than 70%after freeze-thaw test,which meets the specification requirements of non-load-bearing fiber reinforced cement board.Phosphogypsum aggregates have a minor reinforcing effect on the composites,which is relatively optimal at 20%;Based on the above research,a benchmark mix ratio for fiber-reinforced cement-based composite materials incorporating phosphogypsum waste has been proposed.This mix ratio effectively utilizes phosphogypsum waste at 155.39 kg/m^(3),reduces cement consumption by 78.58 kg/m^(3),and lowers carbon dioxide emissions by 27.60 kg/m^(3).Microscopic analysis reveals that dihydrate phosphogypsum,ettringite,and C-S-H gel interpenetrate to form a three-dimensional s

关 键 词：固废磷石膏 纤维增强水泥基复合材料 强度特性 微观机制 绿色环保 

分 类 号：TB332[一般工业技术—材料科学与工程]