Influence of slag chemistry on the hydration of alkali-activated blast-furnace slag — Part I: Effect of MgO |
| |
Authors: | M Ben Haha B Lothenbach G Le Saout F Winnefeld |
| |
Affiliation: | aEmpa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Concrete and Construction Chemistry, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland |
| |
Abstract: | The hydration and the microstructure of three alkali activated slags (AAS) with MgO contents between 8 and 13 wt.% are investigated. The slags were hydrated in the presence of two different alkaline activators, NaOH and Na2SiO3·5H2O (WG). Higher MgO content of the slag resulted in a faster reaction and higher compressive strengths during the first days. The formation of C(− A)–S–H and of a hydrotalcite-like phase was observed in all samples by X-ray diffraction (XRD), thermal analysis (TGA) and scanning electron microscopy (SEM) techniques. Increasing the MgO content of the slag from 8 to 13% increased the amount of hydrotalcite and lowered the Al uptake by C–S–H resulting in 9% higher volume of the hydrates and a 50 to 80% increase of the compressive strength after 28 days and longer for WG activated slag pastes. For NaOH activated slags only a slight increase of the compressive strength was measured. |
| |
Keywords: | Alkali activated slags D MgO (D) Hydration mechanisms A Microstructure (B) Mechanical strength C |
本文献已被 ScienceDirect 等数据库收录! |