摘要
镁合金被誉为“21世纪绿色工程金属结构材料”,我国皮江法炼镁所得镁渣规模庞大、亟待解决,制备建筑材料是消纳镁渣的重要渠道,但国内外相关研究屈指可数,且普遍以镁渣耦合其他固废及水泥制备复合胶凝材料为主,鲜有针对镁渣-水泥简单体系的细致研究,故镁渣水化及其对水泥水化的影响机制尚未明确。本工作通过探究超细镁渣微粉-水泥复合胶凝材料(MS-C)新拌浆体和硬化浆体的性能、组成及结构演化规律,分析超细镁渣微粉对MS-C水化进程的影响机制,进一步揭示镁渣-水泥的协同水化机理。镁渣中的硅酸二钙以低活性γ-C_(2)S为主,超细粉磨是发挥其填充效应的关键途径,掺入30%的超细镁渣粉使水泥中1000 nm以上孔含量由7.98%降低至6.83%。在减水剂作用下,MS-C浆体的流动性随超细镁渣微粉掺量的增大而增大,在无减水剂时其作用相反。低掺量超细镁渣微粉的水化及弱胶凝作用可增大其填充效应对强度的贡献,并促进Ca(OH)_(2)和C-S-H凝胶的生成,使得低超细镁渣微粉掺量的MS-C获得优于纯水泥的28 d力学性能。本研究获得了超细镁渣微粉-水泥水化特性的基础结论,为提高镁渣资源化利用价值及利用率提供理论依据。
Magnesium alloy is known as the green engineering metal structure material in 21^(st) century.The massive magnesium slag produced in China via Pidgeon process has become a crucial problem.Much solid waste can be reused in building materials preparation,and magnesium slag are no exception but are rarely studied.The researches mainly concerned in the cementitious materials prepared from magnesium slag coupled other solid wastes and cement,so the hydration mechanism of magnesium slag and its effect on cement hydration is not clear yet.In this work,the properties,composition and structural of ultrafine magnesium slag powder-cement composites cementitious materials(MS-C)were investigated,and the influence of ultrafine magnesium slag powder on the hydration process of MS-C were discussed,further unlocking the cooperative hydration mechanism of MS-C.The low reactiveγ-C_(2)S is the main form of dicalcium silicate in magnesium slag,so the ultrafine grinding is the key way to improve its filling effect.The content of pore larger than 1000 nm in cement pastes was reduced from 7.98%to 6.83%when 30%of ultrafine magnesium slag powder was blended.The fluidity of MS-C fresh pastes increased with the addition of ultrafine magnesium slag powder under the action of superplasticizer,but the effect was opposite when there was no superplasticizer.The hydration and weak cementing of ultrafine magnesium slag powder with low dosage can enhance the contribution of its filling effect to strength,in which process more Ca(OH)_(2) and C-S-H gel were formed.Therefore,MS-C with low dosage of ultrafine magnesium slag powder obtained better mechanical properties than cement 28 d.The conclusions on the hydration characteristics of ultrafine magnesium slag powder-cement made in this study may provide a theoretical basis for improving the utilization value and rate of magnesium slag.
作者
孙睿
邬兆杰
王栋民
丁源
房奎圳
SUN Rui;WU Zhaojie;WANG Dongmin;DING Yuan;FANG Kuizhen(School of Chemical and Environmental Engineering,China University of Mining and TechnologyBeijing,Beijing 100083,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2023年第9期94-104,共11页
Materials Reports
基金
国家重点研发计划项目(2019YFC1904302,2019YFC1907202)。
关键词
超细镁渣微粉
固体废弃物
复合胶凝材料
力学性能
水化进程
填充效应
孔结构
ultrafine magnesium slag powder
solid wastes
composite cementitious materials
mechanical property
hydration process
filling effect
pore structures
