偏高岭土对浮石轻骨料混凝土强度和孔结构的影响

Influence of Metakaolin to Pumic Lightweight Aggregate Concrete Strength and Pore Structure

通过偏高岭土(MK)取代相同质量的水泥(取代率为0%、5%、10%、15%和20%)配制浮石轻骨料混凝土,分析MK对混凝土性能的影响。对偏高岭土混凝土的立方体抗压强度进行试验研究,并采用核磁共振(NMR)对其微观结构进行分析,得到相应的T_2谱和孔径比例分布图。结果表明:偏高岭土对浮石轻骨料混凝土的抗压强度有很大提高,尤其对早期强度贡献比较大;浮石轻骨料混凝土的T_2谱分布主要有3个峰,偏高岭土的掺入可以优化孔结构,当其取代率为10%时,混凝土的力学性能表现最优,毛细孔和非毛细孔所占比例最小,胶凝孔比例变化与力学变化规律一致。

Replace cement(0%,5%,10%,15%,20%)of the same quality with Metakaolin(MK)to allocate Pumice lightweight aggregate concrete,then to analyzed influence of MK on concrete performance.The cubic concrete compressive strength of metakaolin was tested and the microstructure of concrete was analyzed by nuclear magnetic resonance(NMR),the corresponding T 2 spectrum and aperture ratio distribution maps were obtained.The results show that the addition of metakaolin can improve the compressive strength of pumice lightweight aggregate concrete,especially for early strength.The T 2 spectrum distribution of pumice lightweight aggregate concrete has 3 peaks and the incorporation of metakaolin can optimize the pore structure.When the substitution rate of metakaolin is 10%,the mechanical properties of concrete were optimal,the proportion of capillary pores and non-capillary pores is the smallest,and the proportion of gelling pores is consistent with the mechanical variation.