The Mechanical Properties of Alkali-Activated Slag-Silica Fume Cement Pastes by Mixing Method

Abstract

The mixing method is the investigation of the characteristics of alkali-activated cement paste (AACP) with slag and silica fume (SF) of 1: 1. The basic mixing method is ASTM C305, which is defined as 1st-cycle. There are three factors considered in this experiment; (i) the addition of mixing time (2nd-cycle), (ii) the concentration of activator depending on the amount of mixing water, and (iii) the mixing sequence of slag and SF. It was found that the second cycle, the additional mixing time, had the effect of improving the mechanical properties. In addition, accelerated activation through the mixing of slag with a high concentration of alkali solution in the 1st-cycle increases the hydration products and decreases the porosity and increases the mechanical properties. Therefore, it was found that the change of the mixing method in the AACP composed of slag and SF 1: 1 has a great influence on the mechanical properties. As a result, the method of first mixing slag in aqueous solution of high alkali concentration in AASC mixed with slag and SF improves the mechanical properties.