Influence of alkali lactates on hydration of supersulfated cement: Fid-Bau Portal

Influence of alkali lactates on hydration of supersulfated cement

Masoudi, R. / Hooton, R.D.

Highlights • Low-alumina slag does not have the ideal chemical composition for use in supersulfated cement (SSC). • The poor mechanical performance of low-alumina slag in SSC mixtures was attributed to its low dissolution rate. • Addition of alkali lactates to the mixing water prior to addition of the SSC resulted in increased dissolution of the glass slag and formation of more hydrates. • The increased dissolution of the glass slag was attributed to the chelate effect of the alkali lactates and increased pH of the pore solution. • The increased dissolution of the slag glass resulted in higher concentrations of dissolved Ca, Al, Mg, and Si that thus resulting in higher precipitation of hydration products which ultimately contribute to the compressive strength development of SSC. • The use of alkali lactates significantly increased the compressive strength development of SSC mixtures made with low-alumina slag.

Abstract Supersulfated cement (SSC) is potentially an environmentally attractive alternative to portland cement for use in concrete as it is mainly composed of industrial by-product granulated iron blast-furnace slag and calcium sulfate, with only a small amount of alkali activator. The low-alumina content (<11%), slags produced in North American blast furnaces do not possess the optimum chemical composition for strength development when used in SSC. The main purpose of this study was to investigate the activation of low-alumina slag to increase its potential usefulness in SSC. To improve the performance of low-alumina slag in SSC, the influence of lactic acid salts such as Na and K-lactate were examined and proved to be an effective activation technique for improving the compressive strength of SSC mixtures.