Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11012634 | Construction and Building Materials | 2018 | 12 Pages |
Abstract
High strength fly ash (FA)-based geopolymer pastes containing slag were characterized by means of X-ray diffraction (XRD), thermogravimetry (TGA), and environmental scanning electron microscopy (ESEM). Various ratios of FA were replaced with ground granulated blast furnace slag (GGBS) to enhance the early strength development of the geopolymers cured at room temperature. Compressive and flexural strength tests were conducted to determine the mechanical properties, and mercury intrusion porosimetry (MIP) measurements were carried out to investigate the microstructure of the hardened geopolymers. A new pre-conditioning drying method for MIP investigations was applied and its effects on the GPs' microstructure were evaluated. The comparison of results showed that freeze-drying by using liquid nitrogen could be a great alternative to the conventional drying methods for geopolymers. The compressive and flexural strengths of geopolymers containing slag reached up to around 100â¯MPa and 10â¯MPa, respectively. The decreasing porosity of the geopolymers correlated well with the obtained increasing values of the compressive strength. However, neither of them noticeably improved when over 50% of FA was replaced by GGBS, while a further increase in the flexural strength was observed.
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Authors
Mohammad Ali Yazdi, Marco Liebscher, Simone Hempel, Jian Yang, Viktor Mechtcherine,