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Open AccessArticle

Preparation and Properties of Alkali Activated Metakaolin-Based Geopolymer

by Liang Chen 1,2,*, Zaiqin Wang 1,2, Yuanyi Wang 1,2 and Jing Feng 1,2
Materials and Structural Department, Changjiang River Scientific Research Institute, Wuhan 430010, China
Collaborative Innovation Center for Geo-Hazards and Eco-Environment in Three Gorges Area, Yichang 443002, China
Author to whom correspondence should be addressed.
Academic Editors: Arie van Riessen and Claudio Ferone
Materials 2016, 9(9), 767;
Received: 14 May 2016 / Revised: 30 August 2016 / Accepted: 2 September 2016 / Published: 8 September 2016
(This article belongs to the Special Issue Advances in Geopolymers and Alkali-Activated Materials)
The effective activation and utilization of metakaolin as an alkali activated geopolymer precursor and its use in concrete surface protection is of great interest. In this paper, the formula of alkali activated metakaolin-based geopolymers was studied using an orthogonal experimental design. It was found that the optimal geopolymer was prepared with metakaolin, sodium hydroxide, sodium silicate and water, with the molar ratio of SiO2:Al2O3:Na2O:NaOH:H2O being 3.4:1.1:0.5:1.0:11.8. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were adopted to investigate the influence of curing conditions on the mechanical properties and microstructures of the geopolymers. The best curing condition was 60 °C for 168 h, and this alkali activated metakaolin-based geopolymer showed the highest compression strength at 52.26 MPa. In addition, hollow micro-sphere glass beads were mixed with metakaolin particles to improve the thermal insulation properties of the alkali activated metakaolin-based geopolymer. These results suggest that a suitable volume ratio of metakaolin to hollow micro-sphere glass beads in alkali activated metakaolin-based geopolymers was 6:1, which achieved a thermal conductivity of 0.37 W/mK and compressive strength of 50 MPa. By adjusting to a milder curing condition, as-prepared alkali activated metakaolin-based geopolymers could find widespread applications in concrete thermal protection. View Full-Text
Keywords: alkali activated; geopolymer; metakaolin; curing condition; thermal insulation alkali activated; geopolymer; metakaolin; curing condition; thermal insulation
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MDPI and ACS Style

Chen, L.; Wang, Z.; Wang, Y.; Feng, J. Preparation and Properties of Alkali Activated Metakaolin-Based Geopolymer. Materials 2016, 9, 767.

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