Fresh Properties and Compressive Strength of High Calcium Alkali Activated Fly Ash Mortar
This paper reports the fresh properties and compressive strength of high calcium alkali-activated fly ash (AAFA) mortar. Two different sources of class C fly ash, with different chemical compositions were used to prepare alkali-activated mortar mixtures. Four different sodium silicate to sodium hydroxide (SS/SH) ratios of 0.5, 1.0, 1.5, and 2.5 were used as alkaline activators with a constant sodium hydroxide concentration of 10 M. Two curing regimes were also applied, oven curing at 70 °C for 24 h, and ambient curing at 23 ± 2 °C. The rest time, i.e., the time between casting the mortar cubes and starting the oven curing was 2 h. The results revealed that the setting time, and workability of mortar decreased with increasing the alkali to fly ash ratio, and decreasing the water to fly ash ratio. The optimum sodium silicate to sodium hydroxide ratio was 1.0, which showed the highest compressive strength and setting time. An increase of sodium silicate to sodium hydroxide ratio to 2.5 led to a significant reduction in the setting time, and workability of mortar. The 7-day compressive strength of the mortar approached 20.80 MPa for ambient cured regime and 41.10 for oven cured regime.
E. Gomaa et al., "Fresh Properties and Compressive Strength of High Calcium Alkali Activated Fly Ash Mortar," Journal of King Saud University - Engineering Sciences, vol. 29, no. 4, pp. 356-364, King Saud University, Oct 2017.
The definitive version is available at https://doi.org/10.1016/j.jksues.2017.06.001
Civil, Architectural and Environmental Engineering
International Standard Serial Number (ISSN)
Article - Journal
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01 Oct 2017