CoFeMgAl-LDHs/CNTs复合材料对水泥水化及微观结构的影响  

Effect of CoFeMgAl-LDHs/CNTs Composite Material on Hydration and Microstructure of Cement

作　　者：廖牧情 熊志文 柯国军 邹品玉 宋百姓 金丹 LIAO Muqing;XIONG Zhiwen;KE Guojun;ZOU Pinyu;SONG Baixing;JIN Dan(School of Civil Engineering,University of South China,Hengyang 421001,China;China Nuclear Construction Key Laboratory of High Performance Concrete,Hengyang 421001,China;Hunan Provincial Key Laboratory of High Performance Special Concrete,Hengyang 421001,China)

机构地区：[1]南华大学土木工程学院,衡阳421001 [2]中国核建高性能混凝土实验室,衡阳421001 [3]高性能特种混凝土湖南省重点实验室,衡阳421001

出　　处：《硅酸盐通报》2022年第1期3-12,共10页Bulletin of the Chinese Ceramic Society

基　　金：湖南省自然科学基金衡阳联合项目(2019JJ60003)。

摘　　要：通过进行水化热测试、非蒸发水含量测试、X射线衍射分析、扫描电镜分析、压汞测试及强度试验,研究了钴铁镁铝水滑石-碳纳米管复合材料(CoFeMgAl-LDHs/CNTs)对水泥水化过程、硬化水泥净浆孔结构及强度的影响。结果表明,CoFeMgAl-LDHs/CNTs复合材料通过成核作用显著提升了水泥3 d内的水化程度,从而显著提高了水泥净浆3 d内的抗压强度,3 d后强度提高效果逐渐减小,7 d后复合材料对硬化水泥浆体强度没有明显的提高作用。掺入CoFeMgAl-LDHs/CNTs复合材料的水泥净浆与空白净浆相比,胶凝孔和毛细孔含量明显增多,大孔含量有所降低,同时复合材料的桥联作用进一步优化了水泥净浆的微观结构,从而提高了水泥基体薄弱部位的应力承载能力。因此在同一龄期,复合材料掺入后硬化水泥净浆的强度有所增大。由于复合材料掺量的变化对孔径分布没有明显的影响,改变复合材料的掺量对同龄期硬化水泥净浆强度提升影响较小。Heat of hydration test,non-evaporating water content test,X-ray diffraction analysis,scanning electron microscope analysis,mercury intrusion test and compressive strength tests were used to investigate the effect of the Co-Fe-Mg-Al hydrotalcite carbon nanotubes(CoFeMgAl-LDHs/CNTs)composite material on the hydration process,pore structure and strength of hardened cement paste.The results show that CoFeMgAl-LDHs/CNTs composite material significantly improves the hydration degree of cement within 3 d through nucleation,and thereby significantly enhances the compressive strength of the cement paste in the age of 3 d,the effect of improving the strength gradually reduces after 3 d and become unobvious after 7 d.Compare with blank cement paste,the content of gel pore and capillary pore in hardened cement paste increase obviously,while the macro pore decreases.At the same time,bridging effect of composite material optimizes microstructure of cement paste,and increase the stress bearing capacity of weak parts of cement matrix.Therefore,at the same age,the strength of hardened cement paste is increased.Because the change of composite content has no obvious effect on the change of pore size distribution,the change of composite content has little effect on the strength improvement of hardened cement paste at the same age.

关 键 词：钴铁镁铝水滑石-碳纳米管 水泥净浆 水化 孔结构 强度 成核作用 桥联作用 

分 类 号：TU525[建筑科学—建筑技术科学]