Abstract
This paper presents the effect of elevated temperatures up to 700 degrees C on compressive strength and water absorption of two alkali-activated aluminosilicate composites (one of them is river sand aggregate geopolymer concrete; the other one is crushed sand aggregate geopolymer concrete) and ordinary Portland cement based concretes. To obtain binding geopolymer material, Elaz ferrochrome slag was ground as fine as cement, and then it was alkali activated with chemical (NaOH and Na2SiO3). Geopolymer concrete samples were produced by mixing this binding geopolymer material with aggregates. At each target temperature, concrete samples were exposed to fire for the duration of 1h. Fire resistance and water absorption of geopolymer and ordinary Portland cement concrete samples were determined experimentally. Experimental results indicated that compressive strength of geopolymer concrete samples increased at 100 degrees C and 300 degrees C temperatures when compared with unexposed samples. In geopolymer concrete samples, the highest compressive strength was obtained from river aggregates ones at 300 degrees C with 37.06MPa. Water absorption of geopolymer concrete samples increased at 700 degrees C temperature when compared with unexposed samples. However, a slight decrease in water absorption of concrete samples was observed up to 300 degrees C when compared with unexposed samples. SEM and X-ray diffraction tests were also carried out to investigate microstructure and mineralogical changes during thermal exposure. Copyright (c) 2016 John Wiley & Sons, Ltd.