CONCRETE BASED ON ALKALI ACTIVATED FLY ASH FROM ONE POWER PLANT IN SERBIA

Dragas Jelena, Marinkovic Snezana, Ignjatovic Ivan, Tosic Nikola

Abstract: Alkali activated fly ash concrete (AAFAC) prepared with a class F fly ash from power plant „Nikola Tesla B“ and a mixed alkali activator of sodium silicate and sodium hydroxide solutions was investigated. Firstly, eight alkali activated fly ash pastes (AAFAP) with different activator concentration were tested in order to investigate the effect of this concentration on the compressive strength and workability. These pastes were prepared with different mass ratios of sodium silicate and sodium hydroxide solutions and a mass ratio of total alkali activator to fly ash equal to 0.6. Analyzing the compressive strength, cost and environmental effect of these mixtures, the mixture made with 10M sodium hydroxide solution, and a mass ratio of sodium silicate to sodium hydroxide equal to 10 was chosen as the optimal one for further analysis on concrete. To analyze the influence of additional water on the slump and compressive strength of AAFAC six different mixtures were made and tested. All samples were cured in the oven at the temperature of 80°C for six hours. The results of compressive strength and workability of tested concretes showed that fly ash from power plant „Nikola Tesla B“ can be used as a binder in AAFAC made with sodium silicate and sodium hydroxide as alkali activators

Keywords: Concrete, Fly ash, Alkali activation, Sodium silicate, Sodium hydroxide

DOI: https://doi.org/10.15623/ijret.2014.0325001