Author:
Zhan Jianghuai,Fu Bo,Cheng Zhenyun
Abstract
To investigate the effects of slag and Na2O content on the macroscopic properties and pore structure characteristics of alkali-activated metakaolin–slag (AAMS) composite cementitious materials, this study used X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM-EDS), and mercury-pressure (MIP) tests for characterization and analyzed the hydration product compositions, microstructures, and pore structure characteristics of AAMS composite cementitious materials. The relationships between the fractal dimension and the pore structure parameters, compressive strengths, and drying shrinkage rates of AAMS composite cementitious materials were investigated with the thermodynamic fractal model. The results showed that at the age of 28 d, the compressive strength and drying shrinkage of the AAMS composite binder increased by 20.57% and 215.11%, respectively, when the slag content increased from 0 to 50%. When the Na2O content increased from 8% to 12%, the compressive strength and drying shrinkage of the AAMS composite increased by 24.37% and 129.40%, respectively. The compressive strengths of AAMS composite cementitious materials increased with increasing slag content and Na2O content, but the drying shrinkage of the system increased, and the volume stability worsened. Microscopic analyses showed that with increases in the slag and Na2O contents, the hydration products of AAMS composite cementitious materials increased, and C-A-S-H and N-A-S-H filled each other so that the internal structures of AAMS composite cementitious materials were denser, and the porosities were significantly reduced. By comparing and analyzing the Menger sponge model and the fractal model based on the thermodynamic relationships, it was found that the fractal model based on the thermodynamic relationship better reflected the pore size distribution over the whole pore size determination range, and the correlation coefficients R2 were above 0.99, indicating that the fractal dimension calculated by the fractal model based on the thermodynamic relationship provided a comprehensive evaluation index for the pore structure characteristics of AAMS composite cementitious materials, and the fractal dimension correlated well with the pore structure parameters, compressive strengths, and drying shrinkage rates of cementitious materials.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Ningxia
Key research and development program of Ningxia
Subject
Polymers and Plastics,General Chemistry
Reference63 articles.
1. Advances in alternative cementitious binders;Juenger;Cem. Concr. Res.,2010
2. A review: The comparison between alkali-activated slag (Si+Ca) and metakaolin (Si+Al) cements;Chao;Cem. Concr. Res.,2010
3. Shi, C., Krivenka, P.V., and Della, R. (2008). Alkali-Activated Cement and Concrete, Chemical Industry Press.
4. Formulation and characterization of blended alkali-activated materials based on flash-calcined metakaolin, fly ash and GGBS;Samson;Constr. Build. Mater.,2017
5. Synthesis and heavy metal immobilization behaviors of slag based geopolymer;Zhang;J. Hazard. Mater.,2006
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献