Mechanical properties of concrete composed of sintered fly ash lightweight aggregate

This paper investigates the effect of sintered fly ash lightweight aggregate as coarse aggregate substitution on the mechanical properties of concrete. The lightweight aggregate (LWA) was produced using the cold bonded method and then sintered at a temperature of 900 degrees C. An alkali-activated system was applied as a binding agent of the LWA. Fly ash was used as precursor while sodium hydroxide and sodium silicate were employed as alkali activators. Three variations of the LWA dosage were performed, which were 0%, 50%, and 100 % of the volume of coarse aggregate in the concrete mixture. The mechanical properties of the concrete investigated in this research are the compressive strength and split tensile strength. The result showed that the mechanical properties of the concrete slightly decrease along with the increased dosage of the LWA in the mixture. However, employing sintered fly ash the LWA is proven as an effective solution in reducing the concrete density without sacrificing its strength.