内蒙古农业大学学报（自然科学版）2026，Vol.47Issue(1)：58-65,100,9.DOI:10.16853/j.cnki.1009-3575.2026.01.008
偏高岭土-水泥基复合砂浆的宏观性能及微观孔结构分析
Macroscopic Properties and Micro-pore Structure Analysis of Metakaolin-cement Based Composite Mortar
摘要
Abstract
To investigate the effects of different metakaolin substitution rates on the macro-performance and micro-pore structure of cement-based composite mortar,this study utilized desert sand,manufactured sand,and a combination of desert sand and manufac-tured sand as fine aggregates.M10 mortar was prepared by partially replacing cement with metakaolin at substitution rates of 0%,3%,5%,7%,and 9%.Macro-property tests were conducted to evaluate the workability,mechanical properties,and frost resistance.Additionally,the microscopic morphology and pore structure of the mortar after the frost resistance test were analyzed using field emission scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR).The results showed that with the increase of the content of metakaolin,the water absorption rates of the three mortars decreased.When the substitution rate was 9%,the water absorption rates of desert sand mortar,manufactured sand mortar and mixed sand mortar decrease by 6.7%,9.0%and 7.2%respec-tively,compared to the reference group.Meanwhile,under the same substitution rate,the water retention rates of the three types of mortar increased by 13.9%,13.1%and 13.8%respectively.Mechanical property tests showed that the flexural strength of mortar in-creased first and then decreased with the dosage of metakaolin,and the optimal dosage of 5%for all types.At this dosage,the flexural strengths of desert sand mortar,manufactured sand mortar and mixed sand mortar at the age of 28 days increased by 44.4%,42.5%and 35.9%respectively,compared to the reference group.The freeze-thaw cycle test showed that after 50 cycles,the strength and quality loss rates of the three kinds of mortars all reached the lowest values when the substitution rate was 5%,exhibiting a pattern of first decreasing and then increasing.An appropriate amount of desert sand instead of manufactured sand could enhance the compact-ness of mortar,thereby improving the overall performance of mixed sand mortar.In addition,an appropriate amount of metakaolin could undergo a secondary reaction with cement to generate more CSH cementitious substances,reducing the internal pores of the mortar,and promoting the transformation of large pores into small ones,thereby enhancing the various properties of the mortar.关键词
偏高岭土替代率/沙漠砂砂浆/机制砂砂浆/混合砂砂浆/力学性能/工作性能/抗冻性能Key words
Metakaolin replacement ratio/Desert sand mortar/Manufactured sand mortar/Mixed sand mortar/Mechanical proper-ties/Workability/Frost resistance performance分类
建筑与水利引用本文复制引用
魏迎博,周海龙,吴晓宜..偏高岭土-水泥基复合砂浆的宏观性能及微观孔结构分析[J].内蒙古农业大学学报（自然科学版）,2026,47(1):58-65,100,9.基金项目
内蒙古自然科学基金项目(2024LHMS05026) （2024LHMS05026）
内蒙古自治区研究生教育教学改革项目(JGCG2023065) （JGCG2023065）
